diff --git a/CREDITS b/CREDITS
index d7b8fbf..2d7b29d 100644
--- a/CREDITS
+++ b/CREDITS
@@ -71,6 +71,9 @@ W: https://github.com/engelju
 N: kanlukasz
 W: https://github.com/kanlukasz
 
+N: Kevin Ernst
+W: https://github.com/ernstki
+
 N: Mike-Kennelly
 W: https://github.com/Mike-Kennelly
 
@@ -149,6 +152,9 @@ N: Filip Š
 E: filip.stamcar@hotmail.com
 W: https://www.filips.si/
 
+N: hdk5
+W: https://github.com/hdk5
+
 N: hellojaccc
 E: kim@taekyeong.me
 W: https://github.com/hellojaccc
@@ -225,6 +231,9 @@ N: sean z
 E: ean@vsxd.com
 W: https://vsxd.com/
 
+N: Seth Kinast
+W: https://github.com/sethkinast
+
 N: Sylvain
 E: B00ze64@hotmail.com
 W: https://github.com/B00ze64
diff --git a/README.org b/README.org
index 022eb03..e97ec87 100644
--- a/README.org
+++ b/README.org
@@ -221,6 +221,7 @@ Thanks to all sponsors & contributors to this project for providing help and dev
   - [[https://ko-fi.com/home/coffeeshop?txid=97e5fa0d-c73e-4308-a2fd-6b44b08cd828][Safira]]
   - [[https://ko-fi.com/duncanyoyo1][duncanyoyo1]]
   - [[https://ko-fi.com/home/coffeeshop?txid=a84c4838-f0e8-45b4-8b61-46684697e9b2][Minithra]]
+  - [[https://github.com/black7375/Firefox-UI-Fix/issues/1095#issuecomment-3682151859][Kevin Ernst]]
 - Private sponsors: 5
 
 *Contributors*
diff --git a/__tests__/theme.test.scss b/__tests__/theme.test.scss
index 329a6d2..81ed02f 100644
--- a/__tests__/theme.test.scss
+++ b/__tests__/theme.test.scss
@@ -59,7 +59,7 @@
         }
       }
       @include expect {
-        :root[lwtheme-mozlightdark], :root:is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]) {
+        :root[lwtheme-mozlightdark], :root:is(:is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [builtintheme][devtoolstheme=light]), :is([style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"], [builtintheme][devtoolstheme=dark])) {
           @include example_property;
         }
       }
@@ -74,7 +74,7 @@
         }
       }
       @include expect {
-        :root[lwtheme-mozlightdark][inFullscreen=true], :root:is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"])[inFullscreen=true] {
+        :root[lwtheme-mozlightdark][inFullscreen=true], :root:is(:is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [builtintheme][devtoolstheme=light]), :is([style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"], [builtintheme][devtoolstheme=dark]))[inFullscreen=true] {
           @include example_property;
         }
       }
@@ -89,7 +89,7 @@
         }
       }
       @include expect {
-        :root[lwtheme-mozlightdark] #navigator-toolbox, :root:is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]) #navigator-toolbox {
+        :root[lwtheme-mozlightdark] #navigator-toolbox, :root:is(:is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [builtintheme][devtoolstheme=light]), :is([style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"], [builtintheme][devtoolstheme=dark])) #navigator-toolbox {
           @include example_property;
         }
       }
@@ -106,7 +106,7 @@
         }
       }
       @include expect {
-        :root[lwtheme-mozlightdark]:not([lwthemetextcolor=bright]), :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] {
+        :root[lwtheme-mozlightdark]:not([lwthemetextcolor=bright]), :root:is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [builtintheme][devtoolstheme=light]) {
           @include example_property;
         }
       }
@@ -121,7 +121,7 @@
         }
       }
       @include expect {
-        :root[lwtheme-mozlightdark]:not([lwthemetextcolor=bright])[inFullscreen=true], :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][inFullscreen=true] {
+        :root[lwtheme-mozlightdark]:not([lwthemetextcolor=bright])[inFullscreen=true], :root:is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [builtintheme][devtoolstheme=light])[inFullscreen=true] {
           @include example_property;
         }
       }
@@ -136,7 +136,7 @@
         }
       }
       @include expect {
-        :root[lwtheme-mozlightdark]:not([lwthemetextcolor=bright]) #navigator-toolbox, :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] #navigator-toolbox {
+        :root[lwtheme-mozlightdark]:not([lwthemetextcolor=bright]) #navigator-toolbox, :root:is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [builtintheme][devtoolstheme=light]) #navigator-toolbox {
           @include example_property;
         }
       }
@@ -153,7 +153,7 @@
         }
       }
       @include expect {
-        :root[lwtheme-mozlightdark][lwthemetextcolor=bright], :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] {
+        :root[lwtheme-mozlightdark][lwthemetextcolor=bright], :root:is([style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"], [builtintheme][devtoolstheme=dark]) {
           @include example_property;
         }
       }
@@ -168,7 +168,7 @@
         }
       }
       @include expect {
-        :root[lwtheme-mozlightdark][lwthemetextcolor=bright][inFullscreen=true], :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][inFullscreen=true] {
+        :root[lwtheme-mozlightdark][lwthemetextcolor=bright][inFullscreen=true], :root:is([style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"], [builtintheme][devtoolstheme=dark])[inFullscreen=true] {
           @include example_property;
         }
       }
@@ -183,7 +183,7 @@
         }
       }
       @include expect {
-        :root[lwtheme-mozlightdark][lwthemetextcolor=bright] #navigator-toolbox, :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] #navigator-toolbox {
+        :root[lwtheme-mozlightdark][lwthemetextcolor=bright] #navigator-toolbox, :root:is([style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"], [builtintheme][devtoolstheme=dark]) #navigator-toolbox {
           @include example_property;
         }
       }
diff --git a/css/leptonChrome.css b/css/leptonChrome.css
index 2fbb895..4cbc056 100644
--- a/css/leptonChrome.css
+++ b/css/leptonChrome.css
@@ -5,24 +5,38 @@
 @media -moz-pref("userChrome.theme.built_in_contrast") {
   /*= Lightmode - Color darker =================================================*/
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]),
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    ) {
     --lwt-accent-color: rgb(229, 229, 235) !important; /* Original: rgb(240, 240, 244) */
   }
   @media (-moz-platform: windows) {
     :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]) #navigator-toolbox,
-    :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] #navigator-toolbox {
+    :root:is(
+        [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+        [builtintheme][devtoolstheme="light"]
+      )
+      #navigator-toolbox {
       background-color: var(--lwt-accent-color) !important;
     }
   }
   @media -moz-pref("layout.css.osx-font-smoothing.enabled") {
     :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]) #navigator-toolbox,
-    :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] #navigator-toolbox {
+    :root:is(
+        [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+        [builtintheme][devtoolstheme="light"]
+      )
+      #navigator-toolbox {
       background-color: var(--lwt-accent-color) !important;
     }
   }
   /*= Darkmode - Color lighter =================================================*/
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    ) {
     --toolbar-bgcolor: rgba(43, 42, 51, 5) !important; /* Original: rgba(43, 42, 51, 1) */
   }
 }
@@ -765,9 +779,16 @@
       > .tabbrowser-tab
       > .tab-stack
       > .tab-background[multiselected]:not([selected]),
+    :root[lwtheme-mozlightdark],
     :root:is(
-        [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
-        [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
+        :is(
+            [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+            [builtintheme][devtoolstheme="light"]
+          ),
+        :is(
+            [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+            [builtintheme][devtoolstheme="dark"]
+          )
       )
       #tabbrowser-tabs:not([movingtab])
       > #pinned-tabs-container
@@ -786,9 +807,16 @@
       > .tabbrowser-tab
       > .tab-stack
       > .tab-background[multiselected]:not([selected]),
+    :root[lwtheme-mozlightdark],
     :root:is(
-        [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
-        [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
+        :is(
+            [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+            [builtintheme][devtoolstheme="light"]
+          ),
+        :is(
+            [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+            [builtintheme][devtoolstheme="dark"]
+          )
       )
       #tabbrowser-tabs:not([movingtab])
       > #tabbrowser-arrowscrollbox
@@ -1099,7 +1127,10 @@
         > .tabbrowser-tab
         > .tab-stack
         > .tab-background[selected],
-      :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][lwt-default-theme-in-dark-mode]
+      :root:is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
         #tabbrowser-tabs:not([movingtab])
         > #pinned-tabs-container
         > .tabbrowser-tab
@@ -1111,7 +1142,10 @@
         > .tabbrowser-tab
         > .tab-stack
         > .tab-background[selected],
-      :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][lwt-default-theme-in-dark-mode]
+      :root:is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
         #tabbrowser-tabs:not([movingtab])
         > #tabbrowser-arrowscrollbox
         > .tabbrowser-tab
@@ -1747,7 +1781,10 @@
         --in-content-link-color-visited: var(--blue-40) !important;
       }
       :root[lwtheme-mozlightdark][lwthemetextcolor="bright"],
-      :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] {
+      :root:is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        ) {
         --button-primary-color: var(--in-content-page-color) !important;
         --button-primary-bgcolor: var(--blue-60) !important;
         --button-primary-hover-bgcolor: var(--blue-50) !important;
@@ -1760,7 +1797,11 @@
       }
       @media -moz-pref("userChrome.decoration.download_panel") {
         :root[lwtheme-mozlightdark][lwthemetextcolor="bright"] #downloadsListBox,
-        :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] #downloadsListBox {
+        :root:is(
+            [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+            [builtintheme][devtoolstheme="dark"]
+          )
+          #downloadsListBox {
           --button-primary-bgcolor: var(--blue-30);
           --button-primary-hover-bgcolor: var(--blue-20);
         }
@@ -1771,9 +1812,15 @@
 @media -moz-pref("userChrome.theme.private") {
   :root[privatebrowsingmode="temporary"],
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"])[privatebrowsingmode="temporary"],
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"],
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"],
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"] {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"] {
     --lwt-additional-images: none !important;
     --lwt-header-image: none !important;
     --lwt-tab-text: rgba(232, 224, 255) !important;
@@ -1807,17 +1854,17 @@
       [lwtheme]
     )
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]:is(
-      :-moz-lwtheme,
-      [lwtheme]
-    )
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]:is(
-      :-moz-lwtheme,
-      [lwtheme]
-    )
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox {
     --lwt-tabs-border-color: var(--focus-outline-color) !important;
   }
@@ -1829,12 +1876,15 @@
       [lwtheme]
     )
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"][lwtheme-image]:is(
-      :-moz-lwtheme,
-      [lwtheme]
-    )
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"][lwtheme-image]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"] #navigator-toolbox,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"][lwtheme-image]:is(
@@ -1842,42 +1892,63 @@
       [lwtheme]
     )
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"][lwtheme-image]:is(
-      :-moz-lwtheme,
-      [lwtheme]
-    )
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"][lwtheme-image]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox {
     background-color: var(--lwt-accent-color) !important;
   }
   :root[privatebrowsingmode="temporary"] #TabsToolbar,
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"])[privatebrowsingmode="temporary"] #TabsToolbar,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]
     #TabsToolbar,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"] #TabsToolbar,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]
     #TabsToolbar {
     --lwt-tab-line-color: var(--focus-outline-color) !important;
   }
   :root[privatebrowsingmode="temporary"] notification-message[message-bar-type="infobar"],
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"])[privatebrowsingmode="temporary"]
     notification-message[message-bar-type="infobar"],
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]
     notification-message[message-bar-type="infobar"],
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"]
     notification-message[message-bar-type="infobar"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]
     notification-message[message-bar-type="infobar"] {
     --message-bar-text-color: var(--lwt-tab-text) !important;
     --in-content-page-color: var(--lwt-tab-text) !important;
   }
   :root[privatebrowsingmode="temporary"] menupopup,
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"])[privatebrowsingmode="temporary"] menupopup,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]
     menupopup,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"] menupopup,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]
     menupopup {
     --menuitem-hover-background-color: #413d54 !important;
     --menu-background-color: #1d1935 !important;
@@ -2025,16 +2096,28 @@
     */
   }
   /* Default theme color preservation */
-  :root[lwtheme-mozlightdark] menupopup:not(#BMB_bookmarksPopup, [placespopup="true"]),
-  :root[lwtheme-mozlightdark] menupopup:is(#goPopup, #historyMenuPopup, #bookmarksMenuPopup),
+  :root[lwtheme-mozlightdark],
   :root:is(
-      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
+      :is(
+          [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+          [builtintheme][devtoolstheme="light"]
+        ),
+      :is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
     )
     menupopup:not(#BMB_bookmarksPopup, [placespopup="true"]),
+  :root[lwtheme-mozlightdark],
   :root:is(
-      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
+      :is(
+          [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+          [builtintheme][devtoolstheme="light"]
+        ),
+      :is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
     )
     menupopup:is(#goPopup, #historyMenuPopup, #bookmarksMenuPopup) {
     --menu-color: var(--toolbar-color, var(--in-content-page-color)) !important;
@@ -3962,7 +4045,7 @@
 
 @media -moz-pref("userChrome.rounding.square_tab") {
   :root {
-    --tab-border-radius: 0 !important; /* Original: 4px */
+    --tab-border-radius: 0px !important; /* Original: 4px */
   }
 }
 @media not -moz-pref("userChrome.rounding.square_tab") {
@@ -3972,7 +4055,7 @@
 }
 @media -moz-pref("userChrome.rounding.square_button") {
   :root {
-    --urlbar-icon-border-radius: 0 !important; /* Original: calc(var(--toolbarbutton-border-radius) - 1px); */
+    --urlbar-icon-border-radius: 0px !important; /* Original: calc(var(--toolbarbutton-border-radius) - 1px); */
   }
   .toolbarbutton-1,
   .toolbarbutton-icon,
@@ -3983,7 +4066,7 @@
   .urlbarView-action,
   toolbarbutton.bookmark-item:not(.subviewbutton),
   #sidebar-switcher-target {
-    --toolbarbutton-border-radius: 0; /* Original: 4px */
+    --toolbarbutton-border-radius: 0px; /* Original: 4px */
   }
   button,
   .close-icon,
@@ -3992,7 +4075,7 @@
   findbar toolbarbutton,
   .notification-button,
   #main-menubar > menu {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 @media -moz-pref("userChrome.rounding.square_tab") or -moz-pref("userChrome.rounding.square_button") {
@@ -4004,13 +4087,13 @@
 }
 @media -moz-pref("userChrome.rounding.square_panel") {
   :root {
-    --arrowpanel-border-radius: 0 !important;
+    --arrowpanel-border-radius: 0px !important;
   }
 }
 @media -moz-pref("userChrome.rounding.square_panelitem") {
   :root {
-    --arrowpanel-menuitem-border-radius: 0 !important;
-    --subviewbutton-border-radius: 0 !important;
+    --arrowpanel-menuitem-border-radius: 0px !important;
+    --subviewbutton-border-radius: 0px !important;
   }
 }
 @media -moz-pref("userChrome.rounding.square_menupopup") {
@@ -4024,17 +4107,17 @@
   xul|menulist > xul|menupopup xul|menu,
   xul|menulist > xul|menupopup xul|menuitem,
   .customization-uidensity-menuitem {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 @media -moz-pref("userChrome.rounding.square_infobox") {
   #sanitizeEverythingWarningBox {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 @media -moz-pref("userChrome.rounding.square_toolbar") {
   :root {
-    --uc-rounding-toolbar: 0;
+    --uc-rounding-toolbar: 0px;
   }
   .container.infobar,
   .container.infobar::before,
@@ -4058,19 +4141,19 @@
   #urlbar-input-container,
   #urlbar-background,
   #searchbar {
-    --toolbarbutton-border-radius: 0;
+    --toolbarbutton-border-radius: 0px;
   }
 }
 @media -moz-pref("userChrome.rounding.square_urlView_item") {
   .urlbarView-row,
   .urlbarView-row-inner {
-    --toolbarbutton-border-radius: 0;
+    --toolbarbutton-border-radius: 0px;
   }
 }
 @media -moz-pref("userChrome.rounding.square_checklabel") {
   input[type="checkbox"],
   .checkbox-check {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 @media -moz-pref("userChrome.rounding.square_dialog") {
@@ -4539,7 +4622,8 @@
   }
 }
 @media -moz-pref("userChrome.padding.urlView_expanding") or -moz-pref("userChrome.urlView.as_commandbar") {
-  #urlbar[breakout][breakout-extend] {
+  /* .browser-titlebar is Vertical Tabbar */
+  #nav-bar:not(.browser-titlebar) #urlbar[breakout][breakout-extend] {
     top: calc(var(--urlbar-container-height) * 2 - var(--urlbar-height)) !important;
     width: var(--urlbar-width) !important;
     position: relative !important;
@@ -4808,8 +4892,7 @@
     padding: unset !important;
     padding-top: 4px !important;
   }
-}
-/*= Popup Panel - Reduce padding =============================================*/
+} /*= Popup Panel - Reduce padding =============================================*/
 @media -moz-pref("userChrome.padding.popup_panel") {
   #protections-popup-main-header-label {
     height: unset !important; /* Original: 37.6px */
@@ -7228,14 +7311,37 @@
     );
     --uc-tab-shadow-color-bundle: var(--tab-line-color, var(--lwt-tab-line-color, rgba(128, 128, 142, 0.9)));
   }
+  #tabbrowser-tabs:not([noshadowfortests]) {
+    /* filter create new stacking context */
+  }
+  #tabbrowser-tabs:not([noshadowfortests]) .tab-background:is([selected], [multiselected]) {
+    box-shadow: unset !important;
+    filter: drop-shadow(0 0 2px rgba(0, 0, 0, 0.4));
+  }
+  #tabbrowser-tabs:not([noshadowfortests])[orient="vertical"]
+    .tab-background:is([selected], [multiselected])
+    .tab-group-line {
+    height: calc(100% + 6px + var(--tab-block-margin));
+    transform: translateY(-2px);
+  }
+  #tabbrowser-tabs:not([noshadowfortests])[expanded][orient="vertical"]
+    .tab-background:is([selected], [multiselected])
+    .tab-group-line {
+    inset-inline-start: calc(-1 * var(--tab-inner-inline-margin)) !important;
+  }
+  #tabbrowser-tabs:not([noshadowfortests]):not([expanded])[orient="vertical"]
+    .tab-background:is([selected], [multiselected])
+    .tab-group-line {
+    inset-inline-start: calc(-1 * var(--tab-inner-inline-margin) + 2px) !important;
+  }
   #tabbrowser-tabs:not([noshadowfortests]) .tab-background:is([selected], [multiselected]) {
     box-shadow: unset !important;
     filter: drop-shadow(0 0 2px rgba(0, 0, 0, 0.4));
   }
   :root:is(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab:is([selected], [multiselected])
@@ -7244,16 +7350,16 @@
     filter: drop-shadow(0 0 1px var(--uc-tab-shadow-color, transparent));
   }
   :root:is(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab[visuallyselected]:not(:focus),
   :root:is(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab[multiselected]:not([visuallyselected]) {
@@ -7262,9 +7368,11 @@
   /* For themes outside of Light and Dark (which are curated by Mozilla), show a thicker border
      around the tab to help themes that are dependent on tab_line to show the selected tab. */
   :root:not(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      :is(
+          [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+          [builtintheme][devtoolstheme="light"]
+        )
+    )
     #TabsToolbar:not([brighttext])
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab:is([visuallyselected], [multiselected])
@@ -7275,9 +7383,11 @@
       drop-shadow(1px -1px 0px var(--uc-tab-shadow-color, transparent)) drop-shadow(0 0 2px rgba(128, 128, 142, 0.5));
   }
   :root:not(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      :is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab:is([visuallyselected], [multiselected])
@@ -7384,18 +7494,18 @@
                 opacity: 0.3;
               }
             }
-            :root:not([customizing="true"])::is(
-                [lwtheme-mozlightdark],
-                [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-              ):is(:-moz-lwtheme, [lwtheme])
+            :root:not([customizing="true"]):is(
+                [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+                [builtintheme][devtoolstheme="dark"]
+              )
               #TabsToolbar[brighttext]
               #tabbrowser-tabs:not([noshadowfortests])
               .tabbrowser-tab[visuallyselected]
               .tab-background::before,
-            :root:not([customizing="true"])::is(
-                [lwtheme-mozlightdark],
-                [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-              ):is(:-moz-lwtheme, [lwtheme])
+            :root:not([customizing="true"]):is(
+                [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+                [builtintheme][devtoolstheme="dark"]
+              )
               #TabsToolbar[brighttext]
               #tabbrowser-tabs:not([noshadowfortests])
               .tabbrowser-tab[visuallyselected]
@@ -7666,9 +7776,17 @@
     border-radius: var(--tab-border-radius, 4px) var(--tab-border-radius, 4px) 0 0 !important;
   }
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]),
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] .tab-context-line,
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )
+    .tab-context-line,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] .tab-context-line {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
+    .tab-context-line {
     --tab-line-color: rgb(10, 132, 255);
   }
   .tabbrowser-tab:is([selected], [multiselected]) .tab-context-line {
@@ -7756,9 +7874,17 @@
     }
     /* selected tab style */
     :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]),
-    :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] .tab-context-line,
+    :root:is(
+        [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+        [builtintheme][devtoolstheme="light"]
+      )
+      .tab-context-line,
     :root[lwtheme-mozlightdark][lwthemetextcolor="bright"],
-    :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] .tab-context-line {
+    :root:is(
+        [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+        [builtintheme][devtoolstheme="dark"]
+      )
+      .tab-context-line {
       --tab-line-color: #45a1ff;
     }
     .tabbrowser-tab:is([selected], [multiselected]) .tab-context-line::before {
@@ -8512,6 +8638,18 @@
     padding-inline-start: 3px !important; /* Original: 0px */
     width: 19px !important; /* Redefine from 19px !important, Original: 17px = (width - padding)  */
   }
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tab-close-button {
+    padding: 2px !important;
+    width: 16px !important;
+    height: 16px !important;
+    background-image: linear-gradient(var(--close-button-extra-background)),
+      linear-gradient(var(--tab-selected-bgcolor, var(--toolbar-bgcolor))), linear-gradient(var(--toolbox-bgcolor)) !important;
+  }
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tab-close-button:-moz-window-inactive {
+    background-image: linear-gradient(var(--close-button-extra-background)),
+      linear-gradient(var(--tab-selected-bgcolor, var(--toolbar-bgcolor))),
+      linear-gradient(var(--toolbox-bgcolor-inactive)) !important;
+  }
 }
 /** Clipped tabs - Show close button at pinned tab ****************************/
 @media -moz-pref("userChrome.tab.close_button_at_pinned") {
@@ -8935,10 +9073,11 @@
       display: block;
       position: absolute;
       top: 50%;
+      left: var(--tab-inline-padding);
       transform: translate(var(--uc-container-position-x), var(--uc-container-position-y));
       /* Shape */
       border-bottom: 2px solid var(--identity-icon-color);
-      width: calc(100% - 30px);
+      width: calc(100% - (var(--tab-inline-padding) + var(--tab-inner-inline-margin)) * 2);
       opacity: 0.75;
     }
     .tabbrowser-tab[visuallyselected] .tab-content::before {
@@ -8949,7 +9088,7 @@
         width: 25%;
       }
       .tabbrowser-tab[visuallyselected]:not([pinned]) .tab-content::before {
-        width: calc(100% - 30px);
+        width: calc(100% - (var(--tab-inline-padding) + var(--tab-inner-inline-margin)) * 2);
       }
       #tabbrowser-tabs[closebuttons="activetab"] .tabbrowser-tab[visuallyselected]:not([pinned]) .tab-content::before {
         width: calc(100% - 33px);
@@ -8963,12 +9102,17 @@
       }
     }
     /* Pinned Tab */
-    .tabbrowser-tab[pinned] .tab-content::before {
+    .tabbrowser-tab[pinned] .tab-content::before,
+    #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tab-content::before {
+      left: unset;
       transform: translateY(var(--uc-container-position-y));
-      width: 16px;
+      width: 16px !important;
     }
     @media -moz-pref("userChrome.tab.close_button_at_pinned") {
-      .tabbrowser-tab[pinned][visuallyselected]:not([busy]):hover .tab-content::before {
+      .tabbrowser-tab[pinned][visuallyselected]:not([busy]):hover .tab-content::before,
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[visuallyselected]:not([busy]):hover
+        .tab-content::before {
         opacity: 0;
       }
     }
@@ -8976,12 +9120,28 @@
       .tabbrowser-tab:is([image], [pinned])[usercontextid]
         > .tab-stack
         > .tab-content[attention]:not([selected])::before,
-      .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected])::before {
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[image][usercontextid]
+        > .tab-stack
+        > .tab-content[attention]:not([selected])::before,
+      .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected])::before,
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[usercontextid]
+        > .tab-stack
+        > .tab-content[titlechanged]:not([selected])::before {
         opacity: 0;
       }
       /* Pinned Tab - Titlechanged Indicator override */
       .tabbrowser-tab:is([image], [pinned])[usercontextid] > .tab-stack > .tab-content[attention]:not([selected]),
-      .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]) {
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[image][usercontextid]
+        > .tab-stack
+        > .tab-content[attention]:not([selected]),
+      .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]),
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[usercontextid]
+        > .tab-stack
+        > .tab-content[titlechanged]:not([selected]) {
         /* Original: radial-gradient(circle, var(--attention-icon-color), var(--attention-icon-color) 2px, transparent 2px); */
         --dotted-identity-image: radial-gradient(
           circle,
@@ -8993,7 +9153,15 @@
         background-position-x: var(--uc-titlechanged-container-position-x) !important;
       }
       .tabbrowser-tab:is([image], [pinned]) > .tab-stack > .tab-content[attention]:not([selected]),
-      .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]) {
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[image]
+        > .tab-stack
+        > .tab-content[attention]:not([selected]),
+      .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]),
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab
+        > .tab-stack
+        > .tab-content[titlechanged]:not([selected]) {
         /* Original: center bottom calc(6.5px + var(--tabs-navbar-shadow-size)); */
         background-position-y: top var(--uc-container-position-y) !important;
       }
@@ -9001,25 +9169,51 @@
       .tabbrowser-tab:is([image], [pinned])[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
         > .tab-stack
         > .tab-content[attention]:not([selected]),
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[image][usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+        > .tab-stack
+        > .tab-content[attention]:not([selected]),
       .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
         > .tab-stack
-        > .tab-content[pinned][titlechanged]:not([selected]) {
+        > .tab-content[pinned][titlechanged]:not([selected]),
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+        > .tab-stack
+        > .tab-content[titlechanged]:not([selected]) {
         --uc-titlechanged-container-position-x: calc(32% - 1px), calc(50% - 1px), calc(70% - 1px);
       }
       :root[uidensity="compact"]
         .tabbrowser-tab:is([image], [pinned])[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
         > .tab-stack
         > .tab-content[attention]:not([selected]),
+      :root[uidensity="compact"]
+        #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[image][usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+        > .tab-stack
+        > .tab-content[attention]:not([selected]),
       :root[uidensity="compact"]
         .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
         > .tab-stack
-        > .tab-content[pinned][titlechanged]:not([selected]) {
+        > .tab-content[pinned][titlechanged]:not([selected]),
+      :root[uidensity="compact"]
+        #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+        > .tab-stack
+        > .tab-content[titlechanged]:not([selected]) {
         --uc-titlechanged-container-position-x: calc(30% - 1px), calc(50% - 1px), calc(70% - 1px);
       }
     }
     @media -moz-pref("userChrome.tab.container.on_top") {
       .tabbrowser-tab:is([image], [pinned]) > .tab-stack > .tab-content[attention]:not([selected]),
-      .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]) {
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[image]
+        > .tab-stack
+        > .tab-content[attention]:not([selected]),
+      .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]),
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab
+        > .tab-stack
+        > .tab-content[titlechanged]:not([selected]) {
         /* Original: center bottom calc(6.5px + var(--tabs-navbar-shadow-size)); */
         background-position-y: top var(--uc-container-position-y-bottom) !important;
       }
@@ -12471,12 +12665,72 @@
         padding-inline-start: var(--menu-background-padding-default) !important;
         margin-left: 0 !important;
       }
+      :not(menu, #ContentSelectDropdown, #context-navigation)
+        > menupopup:not(.in-menulist)
+        > menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+        > .menu-icon,
+      :not(menu, #ContentSelectDropdown, #context-navigation)
+        > menupopup:not(.in-menulist)
+        > menu:not(.menu-iconic, .in-menulist, [checked="true"])
+        > .menu-icon,
+      menupopup:is(
+          #menu_FilePopup,
+          #menu_EditPopup,
+          #menu_viewPopup,
+          #goPopup,
+          #historyMenuPopup,
+          #bookmarksMenuPopup,
+          #menu_ProfilesPopup,
+          #menu_ToolsPopup,
+          #windowPopup,
+          #menu_HelpPopup,
+          #usercssloader-menupopup,
+          #sidebar-context-menu
+        )
+        menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+        > .menu-icon,
+      menupopup:is(
+          #menu_FilePopup,
+          #menu_EditPopup,
+          #menu_viewPopup,
+          #goPopup,
+          #historyMenuPopup,
+          #bookmarksMenuPopup,
+          #menu_ProfilesPopup,
+          #menu_ToolsPopup,
+          #windowPopup,
+          #menu_HelpPopup,
+          #usercssloader-menupopup,
+          #sidebar-context-menu
+        )
+        menu:not(.menu-iconic, .in-menulist, [checked="true"])
+        > .menu-icon,
+      menupopup:is(#organizeButtonPopup, #maintenanceButtonPopup)
+        > menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+        > .menu-icon,
+      menupopup:is(#viewMenuPopup, #maintenanceButtonPopup)
+        > menu:not(.menu-iconic, .in-menulist, [checked="true"])
+        > .menu-icon,
+      menupopup:is(
+          #context_sendTabToDevicePopupMenu,
+          #context-sendpagetodevice-popup,
+          #context-sendlinktodevice-popup,
+          #frame > menupopup,
+          #spell-dictionaries-menu,
+          #context-ask-chat > menupopup
+        )
+        > menuitem:not([type="checkbox"][checked="true"], [type="radio"])
+        > .menu-icon,
+      .openintabs-menuitem > .menu-icon,
+      #blockedPopupDontShowMessage > .menu-icon,
+      #BMB_viewBookmarksToolbar > .menu-icon,
+      #sidebarMenu-popup:is(menupopup) > .menu-icon,
+      #context_openANewTab.tabmix-newtab-menu-icon > .menu-icon {
+        display: none !important;
+      }
       .menupopup-arrowscrollbox {
         padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
       }
-      menupopup[needsgutter] > :is(menu, menuitem) > .menu-icon {
-        display: none !important;
-      }
     }
     @media (-moz-platform: windows), (-moz-gtk-csd-available) {
       @media -moz-pref("userChrome.theme.non_native_menu") {
@@ -12548,12 +12802,72 @@
             padding-inline-start: var(--menu-background-padding-default) !important;
             margin-left: 0 !important;
           }
+          :not(menu, #ContentSelectDropdown, #context-navigation)
+            > menupopup:not(.in-menulist)
+            > menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+            > .menu-icon,
+          :not(menu, #ContentSelectDropdown, #context-navigation)
+            > menupopup:not(.in-menulist)
+            > menu:not(.menu-iconic, .in-menulist, [checked="true"])
+            > .menu-icon,
+          menupopup:is(
+              #menu_FilePopup,
+              #menu_EditPopup,
+              #menu_viewPopup,
+              #goPopup,
+              #historyMenuPopup,
+              #bookmarksMenuPopup,
+              #menu_ProfilesPopup,
+              #menu_ToolsPopup,
+              #windowPopup,
+              #menu_HelpPopup,
+              #usercssloader-menupopup,
+              #sidebar-context-menu
+            )
+            menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+            > .menu-icon,
+          menupopup:is(
+              #menu_FilePopup,
+              #menu_EditPopup,
+              #menu_viewPopup,
+              #goPopup,
+              #historyMenuPopup,
+              #bookmarksMenuPopup,
+              #menu_ProfilesPopup,
+              #menu_ToolsPopup,
+              #windowPopup,
+              #menu_HelpPopup,
+              #usercssloader-menupopup,
+              #sidebar-context-menu
+            )
+            menu:not(.menu-iconic, .in-menulist, [checked="true"])
+            > .menu-icon,
+          menupopup:is(#organizeButtonPopup, #maintenanceButtonPopup)
+            > menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+            > .menu-icon,
+          menupopup:is(#viewMenuPopup, #maintenanceButtonPopup)
+            > menu:not(.menu-iconic, .in-menulist, [checked="true"])
+            > .menu-icon,
+          menupopup:is(
+              #context_sendTabToDevicePopupMenu,
+              #context-sendpagetodevice-popup,
+              #context-sendlinktodevice-popup,
+              #frame > menupopup,
+              #spell-dictionaries-menu,
+              #context-ask-chat > menupopup
+            )
+            > menuitem:not([type="checkbox"][checked="true"], [type="radio"])
+            > .menu-icon,
+          .openintabs-menuitem > .menu-icon,
+          #blockedPopupDontShowMessage > .menu-icon,
+          #BMB_viewBookmarksToolbar > .menu-icon,
+          #sidebarMenu-popup:is(menupopup) > .menu-icon,
+          #context_openANewTab.tabmix-newtab-menu-icon > .menu-icon {
+            display: none !important;
+          }
           .menupopup-arrowscrollbox {
             padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
           }
-          menupopup[needsgutter] > :is(menu, menuitem) > .menu-icon {
-            display: none !important;
-          }
         }
       }
     }
@@ -14362,26 +14676,40 @@
 @media (-moz-bool-pref: "userChrome.theme.built_in_contrast") {
   /*= Lightmode - Color darker =================================================*/
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]),
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    ) {
     --lwt-accent-color: rgb(229, 229, 235) !important; /* Original: rgb(240, 240, 244) */
   }
   /*= Darkmode - Color lighter =================================================*/
 }
 @media (-moz-bool-pref: "userChrome.theme.built_in_contrast") and (-moz-platform: windows) {
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]) #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] #navigator-toolbox {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )
+    #navigator-toolbox {
     background-color: var(--lwt-accent-color) !important;
   }
 }
 @media (-moz-bool-pref: "userChrome.theme.built_in_contrast") and (-moz-bool-pref: "layout.css.osx-font-smoothing.enabled") {
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]) #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] #navigator-toolbox {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )
+    #navigator-toolbox {
     background-color: var(--lwt-accent-color) !important;
   }
 }
 @media (-moz-bool-pref: "userChrome.theme.built_in_contrast") {
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    ) {
     --toolbar-bgcolor: rgba(43, 42, 51, 5) !important; /* Original: rgba(43, 42, 51, 1) */
   }
 }
@@ -15151,9 +15479,16 @@
     > .tabbrowser-tab
     > .tab-stack
     > .tab-background[multiselected]:not([selected]),
+  :root[lwtheme-mozlightdark],
   :root:is(
-      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
+      :is(
+          [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+          [builtintheme][devtoolstheme="light"]
+        ),
+      :is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
     )
     #tabbrowser-tabs:not([movingtab])
     > #pinned-tabs-container
@@ -15172,9 +15507,16 @@
     > .tabbrowser-tab
     > .tab-stack
     > .tab-background[multiselected]:not([selected]),
+  :root[lwtheme-mozlightdark],
   :root:is(
-      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
+      :is(
+          [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+          [builtintheme][devtoolstheme="light"]
+        ),
+      :is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
     )
     #tabbrowser-tabs:not([movingtab])
     > #tabbrowser-arrowscrollbox
@@ -15497,7 +15839,10 @@
     > .tabbrowser-tab
     > .tab-stack
     > .tab-background[selected],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][lwt-default-theme-in-dark-mode]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
     #tabbrowser-tabs:not([movingtab])
     > #pinned-tabs-container
     > .tabbrowser-tab
@@ -15509,7 +15854,10 @@
     > .tabbrowser-tab
     > .tab-stack
     > .tab-background[selected],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][lwt-default-theme-in-dark-mode]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
     #tabbrowser-tabs:not([movingtab])
     > #tabbrowser-arrowscrollbox
     > .tabbrowser-tab
@@ -16141,7 +16489,10 @@
     --in-content-link-color-visited: var(--blue-40) !important;
   }
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    ) {
     --button-primary-color: var(--in-content-page-color) !important;
     --button-primary-bgcolor: var(--blue-60) !important;
     --button-primary-hover-bgcolor: var(--blue-50) !important;
@@ -16155,7 +16506,11 @@
 }
 @media (-moz-bool-pref: "userChrome.theme.proton_color") and (-moz-bool-pref: "userChrome.theme.proton_color.dark_blue_accent") and (prefers-color-scheme: dark) and (-moz-bool-pref: "userChrome.decoration.download_panel") {
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"] #downloadsListBox,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] #downloadsListBox {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
+    #downloadsListBox {
     --button-primary-bgcolor: var(--blue-30);
     --button-primary-hover-bgcolor: var(--blue-20);
   }
@@ -16163,9 +16518,15 @@
 @media (-moz-bool-pref: "userChrome.theme.private") {
   :root[privatebrowsingmode="temporary"],
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"])[privatebrowsingmode="temporary"],
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"],
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"],
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"] {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"] {
     --lwt-additional-images: none !important;
     --lwt-header-image: none !important;
     --lwt-tab-text: rgba(232, 224, 255) !important;
@@ -16199,17 +16560,17 @@
       [lwtheme]
     )
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]:is(
-      :-moz-lwtheme,
-      [lwtheme]
-    )
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]:is(
-      :-moz-lwtheme,
-      [lwtheme]
-    )
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox {
     --lwt-tabs-border-color: var(--focus-outline-color) !important;
   }
@@ -16221,12 +16582,15 @@
       [lwtheme]
     )
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"][lwtheme-image]:is(
-      :-moz-lwtheme,
-      [lwtheme]
-    )
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"][lwtheme-image]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"] #navigator-toolbox,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"][lwtheme-image]:is(
@@ -16234,42 +16598,63 @@
       [lwtheme]
     )
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"][lwtheme-image]:is(
-      :-moz-lwtheme,
-      [lwtheme]
-    )
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"][lwtheme-image]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox {
     background-color: var(--lwt-accent-color) !important;
   }
   :root[privatebrowsingmode="temporary"] #TabsToolbar,
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"])[privatebrowsingmode="temporary"] #TabsToolbar,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]
     #TabsToolbar,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"] #TabsToolbar,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]
     #TabsToolbar {
     --lwt-tab-line-color: var(--focus-outline-color) !important;
   }
   :root[privatebrowsingmode="temporary"] notification-message[message-bar-type="infobar"],
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"])[privatebrowsingmode="temporary"]
     notification-message[message-bar-type="infobar"],
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]
     notification-message[message-bar-type="infobar"],
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"]
     notification-message[message-bar-type="infobar"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]
     notification-message[message-bar-type="infobar"] {
     --message-bar-text-color: var(--lwt-tab-text) !important;
     --in-content-page-color: var(--lwt-tab-text) !important;
   }
   :root[privatebrowsingmode="temporary"] menupopup,
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"])[privatebrowsingmode="temporary"] menupopup,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]
     menupopup,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"] menupopup,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]
     menupopup {
     --menuitem-hover-background-color: #413d54 !important;
     --menu-background-color: #1d1935 !important;
@@ -16424,16 +16809,28 @@
   }
 }
 @media (-moz-bool-pref: "userChrome.theme.fully_color") {
-  :root[lwtheme-mozlightdark] menupopup:not(#BMB_bookmarksPopup, [placespopup="true"]),
-  :root[lwtheme-mozlightdark] menupopup:is(#goPopup, #historyMenuPopup, #bookmarksMenuPopup),
+  :root[lwtheme-mozlightdark],
   :root:is(
-      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
+      :is(
+          [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+          [builtintheme][devtoolstheme="light"]
+        ),
+      :is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
     )
     menupopup:not(#BMB_bookmarksPopup, [placespopup="true"]),
+  :root[lwtheme-mozlightdark],
   :root:is(
-      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
+      :is(
+          [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+          [builtintheme][devtoolstheme="light"]
+        ),
+      :is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
     )
     menupopup:is(#goPopup, #historyMenuPopup, #bookmarksMenuPopup) {
     --menu-color: var(--toolbar-color, var(--in-content-page-color)) !important;
@@ -18494,7 +18891,7 @@
 
 @media (-moz-bool-pref: "userChrome.rounding.square_tab") {
   :root {
-    --tab-border-radius: 0 !important; /* Original: 4px */
+    --tab-border-radius: 0px !important; /* Original: 4px */
   }
 }
 @media not (-moz-bool-pref: "userChrome.rounding.square_tab") {
@@ -18504,7 +18901,7 @@
 }
 @media (-moz-bool-pref: "userChrome.rounding.square_button") {
   :root {
-    --urlbar-icon-border-radius: 0 !important; /* Original: calc(var(--toolbarbutton-border-radius) - 1px); */
+    --urlbar-icon-border-radius: 0px !important; /* Original: calc(var(--toolbarbutton-border-radius) - 1px); */
   }
   .toolbarbutton-1,
   .toolbarbutton-icon,
@@ -18515,7 +18912,7 @@
   .urlbarView-action,
   toolbarbutton.bookmark-item:not(.subviewbutton),
   #sidebar-switcher-target {
-    --toolbarbutton-border-radius: 0; /* Original: 4px */
+    --toolbarbutton-border-radius: 0px; /* Original: 4px */
   }
   button,
   .close-icon,
@@ -18524,7 +18921,7 @@
   findbar toolbarbutton,
   .notification-button,
   #main-menubar > menu {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 @media (-moz-bool-pref: "userChrome.rounding.square_tab"), (-moz-bool-pref: "userChrome.rounding.square_button") {
@@ -18536,13 +18933,13 @@
 }
 @media (-moz-bool-pref: "userChrome.rounding.square_panel") {
   :root {
-    --arrowpanel-border-radius: 0 !important;
+    --arrowpanel-border-radius: 0px !important;
   }
 }
 @media (-moz-bool-pref: "userChrome.rounding.square_panelitem") {
   :root {
-    --arrowpanel-menuitem-border-radius: 0 !important;
-    --subviewbutton-border-radius: 0 !important;
+    --arrowpanel-menuitem-border-radius: 0px !important;
+    --subviewbutton-border-radius: 0px !important;
   }
 }
 @media (-moz-bool-pref: "userChrome.rounding.square_menupopup") {
@@ -18556,17 +18953,17 @@
   xul|menulist > xul|menupopup xul|menu,
   xul|menulist > xul|menupopup xul|menuitem,
   .customization-uidensity-menuitem {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 @media (-moz-bool-pref: "userChrome.rounding.square_infobox") {
   #sanitizeEverythingWarningBox {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 @media (-moz-bool-pref: "userChrome.rounding.square_toolbar") {
   :root {
-    --uc-rounding-toolbar: 0;
+    --uc-rounding-toolbar: 0px;
   }
   .container.infobar,
   .container.infobar::before,
@@ -18590,19 +18987,19 @@
   #urlbar-input-container,
   #urlbar-background,
   #searchbar {
-    --toolbarbutton-border-radius: 0;
+    --toolbarbutton-border-radius: 0px;
   }
 }
 @media (-moz-bool-pref: "userChrome.rounding.square_urlView_item") {
   .urlbarView-row,
   .urlbarView-row-inner {
-    --toolbarbutton-border-radius: 0;
+    --toolbarbutton-border-radius: 0px;
   }
 }
 @media (-moz-bool-pref: "userChrome.rounding.square_checklabel") {
   input[type="checkbox"],
   .checkbox-check {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 @media (-moz-bool-pref: "userChrome.rounding.square_dialog") {
@@ -19087,7 +19484,8 @@
   }
 }
 @media (-moz-bool-pref: "userChrome.padding.urlView_expanding"), (-moz-bool-pref: "userChrome.urlView.as_commandbar") {
-  #urlbar[breakout][breakout-extend] {
+  /* .browser-titlebar is Vertical Tabbar */
+  #nav-bar:not(.browser-titlebar) #urlbar[breakout][breakout-extend] {
     top: calc(var(--urlbar-container-height) * 2 - var(--urlbar-height)) !important;
     width: var(--urlbar-width) !important;
     position: relative !important;
@@ -22203,14 +22601,37 @@
     );
     --uc-tab-shadow-color-bundle: var(--tab-line-color, var(--lwt-tab-line-color, rgba(128, 128, 142, 0.9)));
   }
+  #tabbrowser-tabs:not([noshadowfortests]) {
+    /* filter create new stacking context */
+  }
+  #tabbrowser-tabs:not([noshadowfortests]) .tab-background:is([selected], [multiselected]) {
+    box-shadow: unset !important;
+    filter: drop-shadow(0 0 2px rgba(0, 0, 0, 0.4));
+  }
+  #tabbrowser-tabs:not([noshadowfortests])[orient="vertical"]
+    .tab-background:is([selected], [multiselected])
+    .tab-group-line {
+    height: calc(100% + 6px + var(--tab-block-margin));
+    transform: translateY(-2px);
+  }
+  #tabbrowser-tabs:not([noshadowfortests])[expanded][orient="vertical"]
+    .tab-background:is([selected], [multiselected])
+    .tab-group-line {
+    inset-inline-start: calc(-1 * var(--tab-inner-inline-margin)) !important;
+  }
+  #tabbrowser-tabs:not([noshadowfortests]):not([expanded])[orient="vertical"]
+    .tab-background:is([selected], [multiselected])
+    .tab-group-line {
+    inset-inline-start: calc(-1 * var(--tab-inner-inline-margin) + 2px) !important;
+  }
   #tabbrowser-tabs:not([noshadowfortests]) .tab-background:is([selected], [multiselected]) {
     box-shadow: unset !important;
     filter: drop-shadow(0 0 2px rgba(0, 0, 0, 0.4));
   }
   :root:is(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab:is([selected], [multiselected])
@@ -22219,16 +22640,16 @@
     filter: drop-shadow(0 0 1px var(--uc-tab-shadow-color, transparent));
   }
   :root:is(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab[visuallyselected]:not(:focus),
   :root:is(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab[multiselected]:not([visuallyselected]) {
@@ -22237,9 +22658,11 @@
   /* For themes outside of Light and Dark (which are curated by Mozilla), show a thicker border
      around the tab to help themes that are dependent on tab_line to show the selected tab. */
   :root:not(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      :is(
+          [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+          [builtintheme][devtoolstheme="light"]
+        )
+    )
     #TabsToolbar:not([brighttext])
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab:is([visuallyselected], [multiselected])
@@ -22250,9 +22673,11 @@
       drop-shadow(1px -1px 0px var(--uc-tab-shadow-color, transparent)) drop-shadow(0 0 2px rgba(128, 128, 142, 0.5));
   }
   :root:not(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      :is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab:is([visuallyselected], [multiselected])
@@ -22359,18 +22784,18 @@
   }
 }
 @media (-moz-bool-pref: "userChrome.tab.bottom_rounded_corner") and (not (-moz-bool-pref: "userChrome.tab.bottom_rounded_corner.wave")) and (not (-moz-bool-pref: "userChrome.tab.bottom_rounded_corner.australis")) and (not (-moz-bool-pref: "userChrome.tab.bottom_rounded_corner.chrome")) and (not (-moz-bool-pref: "userChrome.tab.bottom_rounded_corner.chrome_legacy")) and (not (-moz-bool-pref: "userChrome.tab.bottom_rounded_corner.edge")) {
-  :root:not([customizing="true"])::is(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+  :root:not([customizing="true"]):is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab[visuallyselected]
     .tab-background::before,
-  :root:not([customizing="true"])::is(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+  :root:not([customizing="true"]):is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab[visuallyselected]
@@ -22760,9 +23185,17 @@
     border-radius: var(--tab-border-radius, 4px) var(--tab-border-radius, 4px) 0 0 !important;
   }
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]),
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] .tab-context-line,
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )
+    .tab-context-line,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] .tab-context-line {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
+    .tab-context-line {
     --tab-line-color: rgb(10, 132, 255);
   }
   .tabbrowser-tab:is([selected], [multiselected]) .tab-context-line {
@@ -22855,9 +23288,17 @@
   }
   /* selected tab style */
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]),
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] .tab-context-line,
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )
+    .tab-context-line,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] .tab-context-line {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
+    .tab-context-line {
     --tab-line-color: #45a1ff;
   }
   .tabbrowser-tab:is([selected], [multiselected]) .tab-context-line::before {
@@ -23656,6 +24097,20 @@
     width: 19px !important; /* Redefine from 19px !important, Original: 17px = (width - padding)  */
   }
 }
+@media (-moz-bool-pref: "userChrome.tab.close_button_at_hover") {
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tab-close-button {
+    padding: 2px !important;
+    width: 16px !important;
+    height: 16px !important;
+    background-image: linear-gradient(var(--close-button-extra-background)),
+      linear-gradient(var(--tab-selected-bgcolor, var(--toolbar-bgcolor))), linear-gradient(var(--toolbox-bgcolor)) !important;
+  }
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tab-close-button:-moz-window-inactive {
+    background-image: linear-gradient(var(--close-button-extra-background)),
+      linear-gradient(var(--tab-selected-bgcolor, var(--toolbar-bgcolor))),
+      linear-gradient(var(--toolbox-bgcolor-inactive)) !important;
+  }
+}
 /** Clipped tabs - Show close button at pinned tab ****************************/
 @media (-moz-bool-pref: "userChrome.tab.close_button_at_pinned") and (not (-moz-bool-pref: "userChrome.tabbar.as_titlebar")) {
   #tabbrowser-tabs {
@@ -24110,10 +24565,11 @@
     display: block;
     position: absolute;
     top: 50%;
+    left: var(--tab-inline-padding);
     transform: translate(var(--uc-container-position-x), var(--uc-container-position-y));
     /* Shape */
     border-bottom: 2px solid var(--identity-icon-color);
-    width: calc(100% - 30px);
+    width: calc(100% - (var(--tab-inline-padding) + var(--tab-inner-inline-margin)) * 2);
     opacity: 0.75;
   }
 }
@@ -24127,7 +24583,7 @@
     width: 25%;
   }
   .tabbrowser-tab[visuallyselected]:not([pinned]) .tab-content::before {
-    width: calc(100% - 30px);
+    width: calc(100% - (var(--tab-inline-padding) + var(--tab-inner-inline-margin)) * 2);
   }
   #tabbrowser-tabs[closebuttons="activetab"] .tabbrowser-tab[visuallyselected]:not([pinned]) .tab-content::before {
     width: calc(100% - 33px);
@@ -24140,24 +24596,45 @@
   }
 }
 @media (-moz-bool-pref: "userChrome.tab.container") and (not (-moz-bool-pref: "userChrome.tabbar.as_titlebar")) {
-  .tabbrowser-tab[pinned] .tab-content::before {
+  .tabbrowser-tab[pinned] .tab-content::before,
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tab-content::before {
+    left: unset;
     transform: translateY(var(--uc-container-position-y));
-    width: 16px;
+    width: 16px !important;
   }
 }
 @media (-moz-bool-pref: "userChrome.tab.container") and (not (-moz-bool-pref: "userChrome.tabbar.as_titlebar")) and (-moz-bool-pref: "userChrome.tab.close_button_at_pinned") {
-  .tabbrowser-tab[pinned][visuallyselected]:not([busy]):hover .tab-content::before {
+  .tabbrowser-tab[pinned][visuallyselected]:not([busy]):hover .tab-content::before,
+  #tabbrowser-tabs[orient="vertical"]:not([expanded])
+    .tabbrowser-tab[visuallyselected]:not([busy]):hover
+    .tab-content::before {
     opacity: 0;
   }
 }
 @media (-moz-bool-pref: "userChrome.tab.container") and (not (-moz-bool-pref: "userChrome.tabbar.as_titlebar")) and (not (-moz-bool-pref: "userChrome.tab.container.on_top")) {
   .tabbrowser-tab:is([image], [pinned])[usercontextid] > .tab-stack > .tab-content[attention]:not([selected])::before,
-  .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected])::before {
+  #tabbrowser-tabs[orient="vertical"]:not([expanded])
+    .tabbrowser-tab[image][usercontextid]
+    > .tab-stack
+    > .tab-content[attention]:not([selected])::before,
+  .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected])::before,
+  #tabbrowser-tabs[orient="vertical"]:not([expanded])
+    .tabbrowser-tab[usercontextid]
+    > .tab-stack
+    > .tab-content[titlechanged]:not([selected])::before {
     opacity: 0;
   }
   /* Pinned Tab - Titlechanged Indicator override */
   .tabbrowser-tab:is([image], [pinned])[usercontextid] > .tab-stack > .tab-content[attention]:not([selected]),
-  .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]) {
+  #tabbrowser-tabs[orient="vertical"]:not([expanded])
+    .tabbrowser-tab[image][usercontextid]
+    > .tab-stack
+    > .tab-content[attention]:not([selected]),
+  .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]),
+  #tabbrowser-tabs[orient="vertical"]:not([expanded])
+    .tabbrowser-tab[usercontextid]
+    > .tab-stack
+    > .tab-content[titlechanged]:not([selected]) {
     /* Original: radial-gradient(circle, var(--attention-icon-color), var(--attention-icon-color) 2px, transparent 2px); */
     --dotted-identity-image: radial-gradient(
       circle,
@@ -24169,7 +24646,15 @@
     background-position-x: var(--uc-titlechanged-container-position-x) !important;
   }
   .tabbrowser-tab:is([image], [pinned]) > .tab-stack > .tab-content[attention]:not([selected]),
-  .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]) {
+  #tabbrowser-tabs[orient="vertical"]:not([expanded])
+    .tabbrowser-tab[image]
+    > .tab-stack
+    > .tab-content[attention]:not([selected]),
+  .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]),
+  #tabbrowser-tabs[orient="vertical"]:not([expanded])
+    .tabbrowser-tab
+    > .tab-stack
+    > .tab-content[titlechanged]:not([selected]) {
     /* Original: center bottom calc(6.5px + var(--tabs-navbar-shadow-size)); */
     background-position-y: top var(--uc-container-position-y) !important;
   }
@@ -24177,25 +24662,51 @@
   .tabbrowser-tab:is([image], [pinned])[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
     > .tab-stack
     > .tab-content[attention]:not([selected]),
+  #tabbrowser-tabs[orient="vertical"]:not([expanded])
+    .tabbrowser-tab[image][usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+    > .tab-stack
+    > .tab-content[attention]:not([selected]),
   .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
     > .tab-stack
-    > .tab-content[pinned][titlechanged]:not([selected]) {
+    > .tab-content[pinned][titlechanged]:not([selected]),
+  #tabbrowser-tabs[orient="vertical"]:not([expanded])
+    .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+    > .tab-stack
+    > .tab-content[titlechanged]:not([selected]) {
     --uc-titlechanged-container-position-x: calc(32% - 1px), calc(50% - 1px), calc(70% - 1px);
   }
   :root[uidensity="compact"]
     .tabbrowser-tab:is([image], [pinned])[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
     > .tab-stack
     > .tab-content[attention]:not([selected]),
+  :root[uidensity="compact"]
+    #tabbrowser-tabs[orient="vertical"]:not([expanded])
+    .tabbrowser-tab[image][usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+    > .tab-stack
+    > .tab-content[attention]:not([selected]),
   :root[uidensity="compact"]
     .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
     > .tab-stack
-    > .tab-content[pinned][titlechanged]:not([selected]) {
+    > .tab-content[pinned][titlechanged]:not([selected]),
+  :root[uidensity="compact"]
+    #tabbrowser-tabs[orient="vertical"]:not([expanded])
+    .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+    > .tab-stack
+    > .tab-content[titlechanged]:not([selected]) {
     --uc-titlechanged-container-position-x: calc(30% - 1px), calc(50% - 1px), calc(70% - 1px);
   }
 }
 @media (-moz-bool-pref: "userChrome.tab.container") and (not (-moz-bool-pref: "userChrome.tabbar.as_titlebar")) and (-moz-bool-pref: "userChrome.tab.container.on_top") {
   .tabbrowser-tab:is([image], [pinned]) > .tab-stack > .tab-content[attention]:not([selected]),
-  .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]) {
+  #tabbrowser-tabs[orient="vertical"]:not([expanded])
+    .tabbrowser-tab[image]
+    > .tab-stack
+    > .tab-content[attention]:not([selected]),
+  .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]),
+  #tabbrowser-tabs[orient="vertical"]:not([expanded])
+    .tabbrowser-tab
+    > .tab-stack
+    > .tab-content[titlechanged]:not([selected]) {
     /* Original: center bottom calc(6.5px + var(--tabs-navbar-shadow-size)); */
     background-position-y: top var(--uc-container-position-y-bottom) !important;
   }
@@ -28260,12 +28771,72 @@
     padding-inline-start: var(--menu-background-padding-default) !important;
     margin-left: 0 !important;
   }
+  :not(menu, #ContentSelectDropdown, #context-navigation)
+    > menupopup:not(.in-menulist)
+    > menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+    > .menu-icon,
+  :not(menu, #ContentSelectDropdown, #context-navigation)
+    > menupopup:not(.in-menulist)
+    > menu:not(.menu-iconic, .in-menulist, [checked="true"])
+    > .menu-icon,
+  menupopup:is(
+      #menu_FilePopup,
+      #menu_EditPopup,
+      #menu_viewPopup,
+      #goPopup,
+      #historyMenuPopup,
+      #bookmarksMenuPopup,
+      #menu_ProfilesPopup,
+      #menu_ToolsPopup,
+      #windowPopup,
+      #menu_HelpPopup,
+      #usercssloader-menupopup,
+      #sidebar-context-menu
+    )
+    menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+    > .menu-icon,
+  menupopup:is(
+      #menu_FilePopup,
+      #menu_EditPopup,
+      #menu_viewPopup,
+      #goPopup,
+      #historyMenuPopup,
+      #bookmarksMenuPopup,
+      #menu_ProfilesPopup,
+      #menu_ToolsPopup,
+      #windowPopup,
+      #menu_HelpPopup,
+      #usercssloader-menupopup,
+      #sidebar-context-menu
+    )
+    menu:not(.menu-iconic, .in-menulist, [checked="true"])
+    > .menu-icon,
+  menupopup:is(#organizeButtonPopup, #maintenanceButtonPopup)
+    > menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+    > .menu-icon,
+  menupopup:is(#viewMenuPopup, #maintenanceButtonPopup)
+    > menu:not(.menu-iconic, .in-menulist, [checked="true"])
+    > .menu-icon,
+  menupopup:is(
+      #context_sendTabToDevicePopupMenu,
+      #context-sendpagetodevice-popup,
+      #context-sendlinktodevice-popup,
+      #frame > menupopup,
+      #spell-dictionaries-menu,
+      #context-ask-chat > menupopup
+    )
+    > menuitem:not([type="checkbox"][checked="true"], [type="radio"])
+    > .menu-icon,
+  .openintabs-menuitem > .menu-icon,
+  #blockedPopupDontShowMessage > .menu-icon,
+  #BMB_viewBookmarksToolbar > .menu-icon,
+  #sidebarMenu-popup:is(menupopup) > .menu-icon,
+  #context_openANewTab.tabmix-newtab-menu-icon > .menu-icon {
+    display: none !important;
+  }
   .menupopup-arrowscrollbox {
     padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
   }
-  menupopup[needsgutter] > :is(menu, menuitem) > .menu-icon {
-    display: none !important;
-  }
 }
 @media (not (-moz-bool-pref: "userChrome.icon.disabled")) and (-moz-bool-pref: "userChrome.icon.menu") and (-moz-platform: windows) and (-moz-bool-pref: "userChrome.theme.non_native_menu") and (-moz-gtk-csd-available),
   (not (-moz-bool-pref: "userChrome.icon.disabled")) and (-moz-bool-pref: "userChrome.icon.menu") and (-moz-gtk-csd-available) and (-moz-bool-pref: "userChrome.theme.non_native_menu") and (-moz-gtk-csd-available) {
@@ -28332,12 +28903,72 @@
     padding-inline-start: var(--menu-background-padding-default) !important;
     margin-left: 0 !important;
   }
+  :not(menu, #ContentSelectDropdown, #context-navigation)
+    > menupopup:not(.in-menulist)
+    > menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+    > .menu-icon,
+  :not(menu, #ContentSelectDropdown, #context-navigation)
+    > menupopup:not(.in-menulist)
+    > menu:not(.menu-iconic, .in-menulist, [checked="true"])
+    > .menu-icon,
+  menupopup:is(
+      #menu_FilePopup,
+      #menu_EditPopup,
+      #menu_viewPopup,
+      #goPopup,
+      #historyMenuPopup,
+      #bookmarksMenuPopup,
+      #menu_ProfilesPopup,
+      #menu_ToolsPopup,
+      #windowPopup,
+      #menu_HelpPopup,
+      #usercssloader-menupopup,
+      #sidebar-context-menu
+    )
+    menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+    > .menu-icon,
+  menupopup:is(
+      #menu_FilePopup,
+      #menu_EditPopup,
+      #menu_viewPopup,
+      #goPopup,
+      #historyMenuPopup,
+      #bookmarksMenuPopup,
+      #menu_ProfilesPopup,
+      #menu_ToolsPopup,
+      #windowPopup,
+      #menu_HelpPopup,
+      #usercssloader-menupopup,
+      #sidebar-context-menu
+    )
+    menu:not(.menu-iconic, .in-menulist, [checked="true"])
+    > .menu-icon,
+  menupopup:is(#organizeButtonPopup, #maintenanceButtonPopup)
+    > menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+    > .menu-icon,
+  menupopup:is(#viewMenuPopup, #maintenanceButtonPopup)
+    > menu:not(.menu-iconic, .in-menulist, [checked="true"])
+    > .menu-icon,
+  menupopup:is(
+      #context_sendTabToDevicePopupMenu,
+      #context-sendpagetodevice-popup,
+      #context-sendlinktodevice-popup,
+      #frame > menupopup,
+      #spell-dictionaries-menu,
+      #context-ask-chat > menupopup
+    )
+    > menuitem:not([type="checkbox"][checked="true"], [type="radio"])
+    > .menu-icon,
+  .openintabs-menuitem > .menu-icon,
+  #blockedPopupDontShowMessage > .menu-icon,
+  #BMB_viewBookmarksToolbar > .menu-icon,
+  #sidebarMenu-popup:is(menupopup) > .menu-icon,
+  #context_openANewTab.tabmix-newtab-menu-icon > .menu-icon {
+    display: none !important;
+  }
   .menupopup-arrowscrollbox {
     padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
   }
-  menupopup[needsgutter] > :is(menu, menuitem) > .menu-icon {
-    display: none !important;
-  }
 }
 @media (not (-moz-bool-pref: "userChrome.icon.disabled")) and (-moz-bool-pref: "userChrome.icon.menu") and (-moz-platform: windows) {
   :root {
diff --git a/css/leptonChromeESR.css b/css/leptonChromeESR.css
index bba6411..4d03477 100644
--- a/css/leptonChromeESR.css
+++ b/css/leptonChromeESR.css
@@ -5,24 +5,38 @@
 @supports -moz-bool-pref("userChrome.theme.built_in_contrast") {
   /*= Lightmode - Color darker =================================================*/
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]),
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    ) {
     --lwt-accent-color: rgb(229, 229, 235) !important; /* Original: rgb(240, 240, 244) */
   }
   @media (-moz-os-version: windows-win10), (-moz-platform: windows-win10) {
     :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]) #navigator-toolbox,
-    :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] #navigator-toolbox {
+    :root:is(
+        [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+        [builtintheme][devtoolstheme="light"]
+      )
+      #navigator-toolbox {
       background-color: var(--lwt-accent-color) !important;
     }
   }
   @supports -moz-bool-pref("layout.css.osx-font-smoothing.enabled") {
     :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]) #navigator-toolbox,
-    :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] #navigator-toolbox {
+    :root:is(
+        [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+        [builtintheme][devtoolstheme="light"]
+      )
+      #navigator-toolbox {
       background-color: var(--lwt-accent-color) !important;
     }
   }
   /*= Darkmode - Color lighter =================================================*/
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    ) {
     --toolbar-bgcolor: rgba(43, 42, 51, 5) !important; /* Original: rgba(43, 42, 51, 1) */
   }
 }
@@ -988,9 +1002,16 @@
       > .tabbrowser-tab
       > .tab-stack
       > .tab-background[multiselected]:not([selected]),
+    :root[lwtheme-mozlightdark],
     :root:is(
-        [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
-        [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
+        :is(
+            [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+            [builtintheme][devtoolstheme="light"]
+          ),
+        :is(
+            [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+            [builtintheme][devtoolstheme="dark"]
+          )
       )
       #tabbrowser-tabs:not([movingtab])
       > #pinned-tabs-container
@@ -1009,9 +1030,16 @@
       > .tabbrowser-tab
       > .tab-stack
       > .tab-background[multiselected]:not([selected]),
+    :root[lwtheme-mozlightdark],
     :root:is(
-        [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
-        [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
+        :is(
+            [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+            [builtintheme][devtoolstheme="light"]
+          ),
+        :is(
+            [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+            [builtintheme][devtoolstheme="dark"]
+          )
       )
       #tabbrowser-tabs:not([movingtab])
       > #tabbrowser-arrowscrollbox
@@ -1322,7 +1350,10 @@
         > .tabbrowser-tab
         > .tab-stack
         > .tab-background[selected],
-      :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][lwt-default-theme-in-dark-mode]
+      :root:is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
         #tabbrowser-tabs:not([movingtab])
         > #pinned-tabs-container
         > .tabbrowser-tab
@@ -1334,7 +1365,10 @@
         > .tabbrowser-tab
         > .tab-stack
         > .tab-background[selected],
-      :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][lwt-default-theme-in-dark-mode]
+      :root:is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
         #tabbrowser-tabs:not([movingtab])
         > #tabbrowser-arrowscrollbox
         > .tabbrowser-tab
@@ -1973,7 +2007,10 @@
         --in-content-link-color-visited: var(--blue-40) !important;
       }
       :root[lwtheme-mozlightdark][lwthemetextcolor="bright"],
-      :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] {
+      :root:is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        ) {
         --button-primary-color: var(--in-content-page-color) !important;
         --button-primary-bgcolor: var(--blue-60) !important;
         --button-primary-hover-bgcolor: var(--blue-50) !important;
@@ -1986,7 +2023,11 @@
       }
       @supports -moz-bool-pref("userChrome.decoration.download_panel") {
         :root[lwtheme-mozlightdark][lwthemetextcolor="bright"] #downloadsListBox,
-        :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] #downloadsListBox {
+        :root:is(
+            [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+            [builtintheme][devtoolstheme="dark"]
+          )
+          #downloadsListBox {
           --button-primary-bgcolor: var(--blue-30);
           --button-primary-hover-bgcolor: var(--blue-20);
         }
@@ -1997,9 +2038,15 @@
 @supports -moz-bool-pref("userChrome.theme.private") {
   :root[privatebrowsingmode="temporary"],
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"])[privatebrowsingmode="temporary"],
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"],
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"],
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"] {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"] {
     --lwt-additional-images: none !important;
     --lwt-header-image: none !important;
     --lwt-tab-text: rgba(232, 224, 255) !important;
@@ -2033,17 +2080,17 @@
       [lwtheme]
     )
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]:is(
-      :-moz-lwtheme,
-      [lwtheme]
-    )
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]:is(
-      :-moz-lwtheme,
-      [lwtheme]
-    )
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox {
     --lwt-tabs-border-color: var(--focus-outline-color) !important;
   }
@@ -2055,12 +2102,15 @@
       [lwtheme]
     )
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"][lwtheme-image]:is(
-      :-moz-lwtheme,
-      [lwtheme]
-    )
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"][lwtheme-image]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"] #navigator-toolbox,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"][lwtheme-image]:is(
@@ -2068,42 +2118,63 @@
       [lwtheme]
     )
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]
     #navigator-toolbox,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"][lwtheme-image]:is(
-      :-moz-lwtheme,
-      [lwtheme]
-    )
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"][lwtheme-image]:is(:-moz-lwtheme, [lwtheme])
     #navigator-toolbox {
     background-color: var(--lwt-accent-color) !important;
   }
   :root[privatebrowsingmode="temporary"] #TabsToolbar,
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"])[privatebrowsingmode="temporary"] #TabsToolbar,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]
     #TabsToolbar,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"] #TabsToolbar,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]
     #TabsToolbar {
     --lwt-tab-line-color: var(--focus-outline-color) !important;
   }
   :root[privatebrowsingmode="temporary"] notification-message[message-bar-type="infobar"],
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"])[privatebrowsingmode="temporary"]
     notification-message[message-bar-type="infobar"],
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]
     notification-message[message-bar-type="infobar"],
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"]
     notification-message[message-bar-type="infobar"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]
     notification-message[message-bar-type="infobar"] {
     --message-bar-text-color: var(--lwt-tab-text) !important;
     --in-content-page-color: var(--lwt-tab-text) !important;
   }
   :root[privatebrowsingmode="temporary"] menupopup,
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"])[privatebrowsingmode="temporary"] menupopup,
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )[privatebrowsingmode="temporary"]
     menupopup,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"][privatebrowsingmode="temporary"] menupopup,
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][privatebrowsingmode="temporary"]
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )[privatebrowsingmode="temporary"]
     menupopup {
     --menuitem-hover-background-color: #413d54 !important;
     --menu-background-color: #1d1935 !important;
@@ -2253,16 +2324,28 @@
     */
   }
   /* Default theme color preservation */
-  :root[lwtheme-mozlightdark] menupopup:not(#BMB_bookmarksPopup, [placespopup="true"]),
-  :root[lwtheme-mozlightdark] menupopup:is(#goPopup, #historyMenuPopup, #bookmarksMenuPopup),
+  :root[lwtheme-mozlightdark],
   :root:is(
-      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
+      :is(
+          [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+          [builtintheme][devtoolstheme="light"]
+        ),
+      :is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
     )
     menupopup:not(#BMB_bookmarksPopup, [placespopup="true"]),
+  :root[lwtheme-mozlightdark],
   :root:is(
-      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
+      :is(
+          [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+          [builtintheme][devtoolstheme="light"]
+        ),
+      :is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
     )
     menupopup:is(#goPopup, #historyMenuPopup, #bookmarksMenuPopup) {
     --menu-color: var(--toolbar-color, var(--in-content-page-color)) !important;
@@ -4283,7 +4366,7 @@
 
 @supports -moz-bool-pref("userChrome.rounding.square_tab") {
   :root {
-    --tab-border-radius: 0 !important; /* Original: 4px */
+    --tab-border-radius: 0px !important; /* Original: 4px */
   }
 }
 @supports not -moz-bool-pref("userChrome.rounding.square_tab") {
@@ -4293,7 +4376,7 @@
 }
 @supports -moz-bool-pref("userChrome.rounding.square_button") {
   :root {
-    --urlbar-icon-border-radius: 0 !important; /* Original: calc(var(--toolbarbutton-border-radius) - 1px); */
+    --urlbar-icon-border-radius: 0px !important; /* Original: calc(var(--toolbarbutton-border-radius) - 1px); */
   }
   .toolbarbutton-1,
   .toolbarbutton-icon,
@@ -4304,7 +4387,7 @@
   .urlbarView-action,
   toolbarbutton.bookmark-item:not(.subviewbutton),
   #sidebar-switcher-target {
-    --toolbarbutton-border-radius: 0; /* Original: 4px */
+    --toolbarbutton-border-radius: 0px; /* Original: 4px */
   }
   button,
   .close-icon,
@@ -4313,7 +4396,7 @@
   findbar toolbarbutton,
   .notification-button,
   #main-menubar > menu {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_tab") or -moz-bool-pref("userChrome.rounding.square_button") {
@@ -4325,13 +4408,13 @@
 }
 @supports -moz-bool-pref("userChrome.rounding.square_panel") {
   :root {
-    --arrowpanel-border-radius: 0 !important;
+    --arrowpanel-border-radius: 0px !important;
   }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_panelitem") {
   :root {
-    --arrowpanel-menuitem-border-radius: 0 !important;
-    --subviewbutton-border-radius: 0 !important;
+    --arrowpanel-menuitem-border-radius: 0px !important;
+    --subviewbutton-border-radius: 0px !important;
   }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_menupopup") {
@@ -4345,17 +4428,17 @@
   xul|menulist > xul|menupopup xul|menu,
   xul|menulist > xul|menupopup xul|menuitem,
   .customization-uidensity-menuitem {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_infobox") {
   #sanitizeEverythingWarningBox {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_toolbar") {
   :root {
-    --uc-rounding-toolbar: 0;
+    --uc-rounding-toolbar: 0px;
   }
   .container.infobar,
   .container.infobar::before,
@@ -4379,19 +4462,19 @@
   #urlbar-input-container,
   #urlbar-background,
   #searchbar {
-    --toolbarbutton-border-radius: 0;
+    --toolbarbutton-border-radius: 0px;
   }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_urlView_item") {
   .urlbarView-row,
   .urlbarView-row-inner {
-    --toolbarbutton-border-radius: 0;
+    --toolbarbutton-border-radius: 0px;
   }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_checklabel") {
   input[type="checkbox"],
   .checkbox-check {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_dialog") {
@@ -4885,7 +4968,8 @@
   }
 }
 @supports -moz-bool-pref("userChrome.padding.urlView_expanding") or -moz-bool-pref("userChrome.urlView.as_commandbar") {
-  #urlbar[breakout][breakout-extend] {
+  /* .browser-titlebar is Vertical Tabbar */
+  #nav-bar:not(.browser-titlebar) #urlbar[breakout][breakout-extend] {
     top: calc(var(--urlbar-container-height) * 2 - var(--urlbar-height)) !important;
     width: var(--urlbar-width) !important;
     position: relative !important;
@@ -7665,14 +7749,37 @@
     );
     --uc-tab-shadow-color-bundle: var(--tab-line-color, var(--lwt-tab-line-color, rgba(128, 128, 142, 0.9)));
   }
+  #tabbrowser-tabs:not([noshadowfortests]) {
+    /* filter create new stacking context */
+  }
+  #tabbrowser-tabs:not([noshadowfortests]) .tab-background:is([selected], [multiselected]) {
+    box-shadow: unset !important;
+    filter: drop-shadow(0 0 2px rgba(0, 0, 0, 0.4));
+  }
+  #tabbrowser-tabs:not([noshadowfortests])[orient="vertical"]
+    .tab-background:is([selected], [multiselected])
+    .tab-group-line {
+    height: calc(100% + 6px + var(--tab-block-margin));
+    transform: translateY(-2px);
+  }
+  #tabbrowser-tabs:not([noshadowfortests])[expanded][orient="vertical"]
+    .tab-background:is([selected], [multiselected])
+    .tab-group-line {
+    inset-inline-start: calc(-1 * var(--tab-inner-inline-margin)) !important;
+  }
+  #tabbrowser-tabs:not([noshadowfortests]):not([expanded])[orient="vertical"]
+    .tab-background:is([selected], [multiselected])
+    .tab-group-line {
+    inset-inline-start: calc(-1 * var(--tab-inner-inline-margin) + 2px) !important;
+  }
   #tabbrowser-tabs:not([noshadowfortests]) .tab-background:is([selected], [multiselected]) {
     box-shadow: unset !important;
     filter: drop-shadow(0 0 2px rgba(0, 0, 0, 0.4));
   }
   :root:is(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab:is([selected], [multiselected])
@@ -7681,16 +7788,16 @@
     filter: drop-shadow(0 0 1px var(--uc-tab-shadow-color, transparent));
   }
   :root:is(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab[visuallyselected]:not(:focus),
   :root:is(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab[multiselected]:not([visuallyselected]) {
@@ -7699,9 +7806,11 @@
   /* For themes outside of Light and Dark (which are curated by Mozilla), show a thicker border
      around the tab to help themes that are dependent on tab_line to show the selected tab. */
   :root:not(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      :is(
+          [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+          [builtintheme][devtoolstheme="light"]
+        )
+    )
     #TabsToolbar:not([brighttext])
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab:is([visuallyselected], [multiselected])
@@ -7712,9 +7821,11 @@
       drop-shadow(1px -1px 0px var(--uc-tab-shadow-color, transparent)) drop-shadow(0 0 2px rgba(128, 128, 142, 0.5));
   }
   :root:not(
-      [lwtheme-mozlightdark],
-      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-    ):is(:-moz-lwtheme, [lwtheme])
+      :is(
+          [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+          [builtintheme][devtoolstheme="dark"]
+        )
+    )
     #TabsToolbar[brighttext]
     #tabbrowser-tabs:not([noshadowfortests])
     .tabbrowser-tab:is([visuallyselected], [multiselected])
@@ -7821,18 +7932,18 @@
                 opacity: 0.3;
               }
             }
-            :root:not([customizing="true"])::is(
-                [lwtheme-mozlightdark],
-                [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-              ):is(:-moz-lwtheme, [lwtheme])
+            :root:not([customizing="true"]):is(
+                [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+                [builtintheme][devtoolstheme="dark"]
+              )
               #TabsToolbar[brighttext]
               #tabbrowser-tabs:not([noshadowfortests])
               .tabbrowser-tab[visuallyselected]
               .tab-background::before,
-            :root:not([customizing="true"])::is(
-                [lwtheme-mozlightdark],
-                [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]
-              ):is(:-moz-lwtheme, [lwtheme])
+            :root:not([customizing="true"]):is(
+                [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+                [builtintheme][devtoolstheme="dark"]
+              )
               #TabsToolbar[brighttext]
               #tabbrowser-tabs:not([noshadowfortests])
               .tabbrowser-tab[visuallyselected]
@@ -8109,9 +8220,17 @@
     border-radius: var(--tab-border-radius, 4px) var(--tab-border-radius, 4px) 0 0 !important;
   }
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]),
-  :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] .tab-context-line,
+  :root:is(
+      [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+      [builtintheme][devtoolstheme="light"]
+    )
+    .tab-context-line,
   :root[lwtheme-mozlightdark][lwthemetextcolor="bright"],
-  :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] .tab-context-line {
+  :root:is(
+      [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+      [builtintheme][devtoolstheme="dark"]
+    )
+    .tab-context-line {
     --tab-line-color: rgb(10, 132, 255);
   }
   .tabbrowser-tab:is([selected], [multiselected]) .tab-context-line {
@@ -8199,9 +8318,17 @@
     }
     /* selected tab style */
     :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]),
-    :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] .tab-context-line,
+    :root:is(
+        [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"],
+        [builtintheme][devtoolstheme="light"]
+      )
+      .tab-context-line,
     :root[lwtheme-mozlightdark][lwthemetextcolor="bright"],
-    :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"] .tab-context-line {
+    :root:is(
+        [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"],
+        [builtintheme][devtoolstheme="dark"]
+      )
+      .tab-context-line {
       --tab-line-color: #45a1ff;
     }
     .tabbrowser-tab:is([selected], [multiselected]) .tab-context-line::before {
@@ -8971,6 +9098,18 @@
     padding-inline-start: 3px !important; /* Original: 0px */
     width: 19px !important; /* Redefine from 19px !important, Original: 17px = (width - padding)  */
   }
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tab-close-button {
+    padding: 2px !important;
+    width: 16px !important;
+    height: 16px !important;
+    background-image: linear-gradient(var(--close-button-extra-background)),
+      linear-gradient(var(--tab-selected-bgcolor, var(--toolbar-bgcolor))), linear-gradient(var(--toolbox-bgcolor)) !important;
+  }
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tab-close-button:-moz-window-inactive {
+    background-image: linear-gradient(var(--close-button-extra-background)),
+      linear-gradient(var(--tab-selected-bgcolor, var(--toolbar-bgcolor))),
+      linear-gradient(var(--toolbox-bgcolor-inactive)) !important;
+  }
 }
 /** Clipped tabs - Show close button at pinned tab ****************************/
 @supports -moz-bool-pref("userChrome.tab.close_button_at_pinned") {
@@ -9394,10 +9533,11 @@
       display: block;
       position: absolute;
       top: 50%;
+      left: var(--tab-inline-padding);
       transform: translate(var(--uc-container-position-x), var(--uc-container-position-y));
       /* Shape */
       border-bottom: 2px solid var(--identity-icon-color);
-      width: calc(100% - 30px);
+      width: calc(100% - (var(--tab-inline-padding) + var(--tab-inner-inline-margin)) * 2);
       opacity: 0.75;
     }
     .tabbrowser-tab[visuallyselected] .tab-content::before {
@@ -9408,7 +9548,7 @@
         width: 25%;
       }
       .tabbrowser-tab[visuallyselected]:not([pinned]) .tab-content::before {
-        width: calc(100% - 30px);
+        width: calc(100% - (var(--tab-inline-padding) + var(--tab-inner-inline-margin)) * 2);
       }
       #tabbrowser-tabs[closebuttons="activetab"] .tabbrowser-tab[visuallyselected]:not([pinned]) .tab-content::before {
         width: calc(100% - 33px);
@@ -9422,12 +9562,17 @@
       }
     }
     /* Pinned Tab */
-    .tabbrowser-tab[pinned] .tab-content::before {
+    .tabbrowser-tab[pinned] .tab-content::before,
+    #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tab-content::before {
+      left: unset;
       transform: translateY(var(--uc-container-position-y));
-      width: 16px;
+      width: 16px !important;
     }
     @supports -moz-bool-pref("userChrome.tab.close_button_at_pinned") {
-      .tabbrowser-tab[pinned][visuallyselected]:not([busy]):hover .tab-content::before {
+      .tabbrowser-tab[pinned][visuallyselected]:not([busy]):hover .tab-content::before,
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[visuallyselected]:not([busy]):hover
+        .tab-content::before {
         opacity: 0;
       }
     }
@@ -9435,12 +9580,28 @@
       .tabbrowser-tab:is([image], [pinned])[usercontextid]
         > .tab-stack
         > .tab-content[attention]:not([selected])::before,
-      .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected])::before {
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[image][usercontextid]
+        > .tab-stack
+        > .tab-content[attention]:not([selected])::before,
+      .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected])::before,
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[usercontextid]
+        > .tab-stack
+        > .tab-content[titlechanged]:not([selected])::before {
         opacity: 0;
       }
       /* Pinned Tab - Titlechanged Indicator override */
       .tabbrowser-tab:is([image], [pinned])[usercontextid] > .tab-stack > .tab-content[attention]:not([selected]),
-      .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]) {
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[image][usercontextid]
+        > .tab-stack
+        > .tab-content[attention]:not([selected]),
+      .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]),
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[usercontextid]
+        > .tab-stack
+        > .tab-content[titlechanged]:not([selected]) {
         /* Original: radial-gradient(circle, var(--attention-icon-color), var(--attention-icon-color) 2px, transparent 2px); */
         --dotted-identity-image: radial-gradient(
           circle,
@@ -9452,7 +9613,15 @@
         background-position-x: var(--uc-titlechanged-container-position-x) !important;
       }
       .tabbrowser-tab:is([image], [pinned]) > .tab-stack > .tab-content[attention]:not([selected]),
-      .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]) {
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[image]
+        > .tab-stack
+        > .tab-content[attention]:not([selected]),
+      .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]),
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab
+        > .tab-stack
+        > .tab-content[titlechanged]:not([selected]) {
         /* Original: center bottom calc(6.5px + var(--tabs-navbar-shadow-size)); */
         background-position-y: top var(--uc-container-position-y) !important;
       }
@@ -9460,25 +9629,51 @@
       .tabbrowser-tab:is([image], [pinned])[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
         > .tab-stack
         > .tab-content[attention]:not([selected]),
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[image][usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+        > .tab-stack
+        > .tab-content[attention]:not([selected]),
       .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
         > .tab-stack
-        > .tab-content[pinned][titlechanged]:not([selected]) {
+        > .tab-content[pinned][titlechanged]:not([selected]),
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+        > .tab-stack
+        > .tab-content[titlechanged]:not([selected]) {
         --uc-titlechanged-container-position-x: calc(32% - 1px), calc(50% - 1px), calc(70% - 1px);
       }
       :root[uidensity="compact"]
         .tabbrowser-tab:is([image], [pinned])[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
         > .tab-stack
         > .tab-content[attention]:not([selected]),
+      :root[uidensity="compact"]
+        #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[image][usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+        > .tab-stack
+        > .tab-content[attention]:not([selected]),
       :root[uidensity="compact"]
         .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
         > .tab-stack
-        > .tab-content[pinned][titlechanged]:not([selected]) {
+        > .tab-content[pinned][titlechanged]:not([selected]),
+      :root[uidensity="compact"]
+        #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+        > .tab-stack
+        > .tab-content[titlechanged]:not([selected]) {
         --uc-titlechanged-container-position-x: calc(30% - 1px), calc(50% - 1px), calc(70% - 1px);
       }
     }
     @supports -moz-bool-pref("userChrome.tab.container.on_top") {
       .tabbrowser-tab:is([image], [pinned]) > .tab-stack > .tab-content[attention]:not([selected]),
-      .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]) {
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab[image]
+        > .tab-stack
+        > .tab-content[attention]:not([selected]),
+      .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]),
+      #tabbrowser-tabs[orient="vertical"]:not([expanded])
+        .tabbrowser-tab
+        > .tab-stack
+        > .tab-content[titlechanged]:not([selected]) {
         /* Original: center bottom calc(6.5px + var(--tabs-navbar-shadow-size)); */
         background-position-y: top var(--uc-container-position-y-bottom) !important;
       }
@@ -12960,12 +13155,72 @@
         padding-inline-start: var(--menu-background-padding-default) !important;
         margin-left: 0 !important;
       }
+      :not(menu, #ContentSelectDropdown, #context-navigation)
+        > menupopup:not(.in-menulist)
+        > menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+        > .menu-icon,
+      :not(menu, #ContentSelectDropdown, #context-navigation)
+        > menupopup:not(.in-menulist)
+        > menu:not(.menu-iconic, .in-menulist, [checked="true"])
+        > .menu-icon,
+      menupopup:is(
+          #menu_FilePopup,
+          #menu_EditPopup,
+          #menu_viewPopup,
+          #goPopup,
+          #historyMenuPopup,
+          #bookmarksMenuPopup,
+          #menu_ProfilesPopup,
+          #menu_ToolsPopup,
+          #windowPopup,
+          #menu_HelpPopup,
+          #usercssloader-menupopup,
+          #sidebar-context-menu
+        )
+        menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+        > .menu-icon,
+      menupopup:is(
+          #menu_FilePopup,
+          #menu_EditPopup,
+          #menu_viewPopup,
+          #goPopup,
+          #historyMenuPopup,
+          #bookmarksMenuPopup,
+          #menu_ProfilesPopup,
+          #menu_ToolsPopup,
+          #windowPopup,
+          #menu_HelpPopup,
+          #usercssloader-menupopup,
+          #sidebar-context-menu
+        )
+        menu:not(.menu-iconic, .in-menulist, [checked="true"])
+        > .menu-icon,
+      menupopup:is(#organizeButtonPopup, #maintenanceButtonPopup)
+        > menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+        > .menu-icon,
+      menupopup:is(#viewMenuPopup, #maintenanceButtonPopup)
+        > menu:not(.menu-iconic, .in-menulist, [checked="true"])
+        > .menu-icon,
+      menupopup:is(
+          #context_sendTabToDevicePopupMenu,
+          #context-sendpagetodevice-popup,
+          #context-sendlinktodevice-popup,
+          #frame > menupopup,
+          #spell-dictionaries-menu,
+          #context-ask-chat > menupopup
+        )
+        > menuitem:not([type="checkbox"][checked="true"], [type="radio"])
+        > .menu-icon,
+      .openintabs-menuitem > .menu-icon,
+      #blockedPopupDontShowMessage > .menu-icon,
+      #BMB_viewBookmarksToolbar > .menu-icon,
+      #sidebarMenu-popup:is(menupopup) > .menu-icon,
+      #context_openANewTab.tabmix-newtab-menu-icon > .menu-icon {
+        display: none !important;
+      }
       .menupopup-arrowscrollbox {
         padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
       }
-      menupopup[needsgutter] > :is(menu, menuitem) > .menu-icon {
-        display: none !important;
-      }
     }
     @media (-moz-os-version: windows-win7),
       (-moz-os-version: windows-win8),
@@ -13044,12 +13299,72 @@
             padding-inline-start: var(--menu-background-padding-default) !important;
             margin-left: 0 !important;
           }
+          :not(menu, #ContentSelectDropdown, #context-navigation)
+            > menupopup:not(.in-menulist)
+            > menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+            > .menu-icon,
+          :not(menu, #ContentSelectDropdown, #context-navigation)
+            > menupopup:not(.in-menulist)
+            > menu:not(.menu-iconic, .in-menulist, [checked="true"])
+            > .menu-icon,
+          menupopup:is(
+              #menu_FilePopup,
+              #menu_EditPopup,
+              #menu_viewPopup,
+              #goPopup,
+              #historyMenuPopup,
+              #bookmarksMenuPopup,
+              #menu_ProfilesPopup,
+              #menu_ToolsPopup,
+              #windowPopup,
+              #menu_HelpPopup,
+              #usercssloader-menupopup,
+              #sidebar-context-menu
+            )
+            menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+            > .menu-icon,
+          menupopup:is(
+              #menu_FilePopup,
+              #menu_EditPopup,
+              #menu_viewPopup,
+              #goPopup,
+              #historyMenuPopup,
+              #bookmarksMenuPopup,
+              #menu_ProfilesPopup,
+              #menu_ToolsPopup,
+              #windowPopup,
+              #menu_HelpPopup,
+              #usercssloader-menupopup,
+              #sidebar-context-menu
+            )
+            menu:not(.menu-iconic, .in-menulist, [checked="true"])
+            > .menu-icon,
+          menupopup:is(#organizeButtonPopup, #maintenanceButtonPopup)
+            > menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"])
+            > .menu-icon,
+          menupopup:is(#viewMenuPopup, #maintenanceButtonPopup)
+            > menu:not(.menu-iconic, .in-menulist, [checked="true"])
+            > .menu-icon,
+          menupopup:is(
+              #context_sendTabToDevicePopupMenu,
+              #context-sendpagetodevice-popup,
+              #context-sendlinktodevice-popup,
+              #frame > menupopup,
+              #spell-dictionaries-menu,
+              #context-ask-chat > menupopup
+            )
+            > menuitem:not([type="checkbox"][checked="true"], [type="radio"])
+            > .menu-icon,
+          .openintabs-menuitem > .menu-icon,
+          #blockedPopupDontShowMessage > .menu-icon,
+          #BMB_viewBookmarksToolbar > .menu-icon,
+          #sidebarMenu-popup:is(menupopup) > .menu-icon,
+          #context_openANewTab.tabmix-newtab-menu-icon > .menu-icon {
+            display: none !important;
+          }
           .menupopup-arrowscrollbox {
             padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
           }
-          menupopup[needsgutter] > :is(menu, menuitem) > .menu-icon {
-            display: none !important;
-          }
         }
       }
     }
diff --git a/install.sh b/install.sh
index ab47194..c051d24 100755
--- a/install.sh
+++ b/install.sh
@@ -345,6 +345,7 @@ firefoxProfileDirPaths=(
   "${HOME}/.local/opt/tor-browser/app/Browser/TorBrowser/Data/Browser"
   "${HOME}/.var/app/org.mozilla.firefox/.mozilla/firefox"
   "${HOME}/.var/app/io.gitlab.librewolf-community/.librewolf"
+  "${HOME}/.var/app/net.waterfox.waterfox/.waterfox"
   "${HOME}/snap/firefox/common/.mozilla/firefox"
   "${HOME}/Library/Application Support/Firefox"
   "${HOME}/Library/Application Support/Waterfox"
diff --git a/src/icons/layout/_menu.scss b/src/icons/layout/_menu.scss
index 1807962..8dd626c 100644
--- a/src/icons/layout/_menu.scss
+++ b/src/icons/layout/_menu.scss
@@ -102,17 +102,17 @@ $_layoutCommonMenus: (
     @include _layout_root_non_native;
     @include _layoutIconMenus {
       @include _layout_init_non_native();
+
+      // FF v141 #1128
+      > .menu-icon {
+        display: none !important;
+      }
     }
 
     // FF v121
     .menupopup-arrowscrollbox {
       padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
     }
-
-    // FF v141 #1128
-    menupopup[needsgutter] > :is(menu, menuitem) > .menu-icon {
-      display: none !important;
-    }
   }
 }
 
diff --git a/src/padding/_index.scss b/src/padding/_index.scss
index 32328f1..4b73926 100644
--- a/src/padding/_index.scss
+++ b/src/padding/_index.scss
@@ -50,7 +50,8 @@
   }
 }
 @include Option("userChrome.padding.urlView_expanding", "userChrome.urlView.as_commandbar") {
-  #urlbar[breakout][breakout-extend] {
+  /* .browser-titlebar is Vertical Tabbar */
+  #nav-bar:not(.browser-titlebar) #urlbar[breakout][breakout-extend] {
     top: calc(var(--urlbar-container-height) * 2 - var(--urlbar-height)) !important;
     width: var(--urlbar-width) !important;
     position: relative !important;
diff --git a/src/rounding/_square.scss b/src/rounding/_square.scss
index 3140184..a2a0341 100644
--- a/src/rounding/_square.scss
+++ b/src/rounding/_square.scss
@@ -1,6 +1,6 @@
 @include Option("userChrome.rounding.square_tab") {
   :root {
-    --tab-border-radius: 0 !important; /* Original: 4px */
+    --tab-border-radius: 0px !important; /* Original: 4px */
   }
 }
 @include NotOption("userChrome.rounding.square_tab") {
@@ -10,7 +10,7 @@
 }
 @include Option("userChrome.rounding.square_button") {
   :root {
-    --urlbar-icon-border-radius: 0 !important; /* Original: calc(var(--toolbarbutton-border-radius) - 1px); */
+    --urlbar-icon-border-radius: 0px !important; /* Original: calc(var(--toolbarbutton-border-radius) - 1px); */
   }
 
   .toolbarbutton-1,
@@ -22,7 +22,7 @@
   .urlbarView-action,
   toolbarbutton.bookmark-item:not(.subviewbutton),
   #sidebar-switcher-target {
-    --toolbarbutton-border-radius: 0;  /* Original: 4px */
+    --toolbarbutton-border-radius: 0px;  /* Original: 4px */
   }
 
   button,
@@ -32,7 +32,7 @@
   findbar toolbarbutton,
   .notification-button,
   #main-menubar > menu {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 @include Option("userChrome.rounding.square_tab", "userChrome.rounding.square_button") {
@@ -45,13 +45,13 @@
 
 @include Option("userChrome.rounding.square_panel") {
   :root {
-    --arrowpanel-border-radius: 0 !important;
+    --arrowpanel-border-radius: 0px !important;
   }
 }
 @include Option("userChrome.rounding.square_panelitem") {
   :root {
-    --arrowpanel-menuitem-border-radius: 0 !important;
-    --subviewbutton-border-radius: 0 !important;
+    --arrowpanel-menuitem-border-radius: 0px !important;
+    --subviewbutton-border-radius: 0px !important;
   }
 }
 
@@ -66,19 +66,19 @@
   xul|menulist > xul|menupopup xul|menu,
   xul|menulist > xul|menupopup xul|menuitem,
   .customization-uidensity-menuitem {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 
 @include Option("userChrome.rounding.square_infobox") {
   #sanitizeEverythingWarningBox {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
 
 @include Option("userChrome.rounding.square_toolbar") {
   :root {
-    --uc-rounding-toolbar: 0;
+    --uc-rounding-toolbar: 0px;
   }
 
   .container.infobar,
@@ -105,20 +105,20 @@
   #urlbar-input-container,
   #urlbar-background,
   #searchbar {
-    --toolbarbutton-border-radius: 0;
+    --toolbarbutton-border-radius: 0px;
   }
 }
 
 @include Option("userChrome.rounding.square_urlView_item") {
   .urlbarView-row, // At FF v111 #668
   .urlbarView-row-inner {
-    --toolbarbutton-border-radius: 0;
+    --toolbarbutton-border-radius: 0px;
   }
 }
 
 @include Option("userChrome.rounding.square_checklabel") {
   input[type="checkbox"],
   .checkbox-check {
-    border-radius: 0 !important;
+    border-radius: 0px !important;
   }
 }
diff --git a/src/tab/_container_tab.scss b/src/tab/_container_tab.scss
index 311680b..4f132eb 100644
--- a/src/tab/_container_tab.scss
+++ b/src/tab/_container_tab.scss
@@ -35,11 +35,12 @@
   display: block;
   position: absolute;
   top: 50%;
+  left: var(--tab-inline-padding);
   transform: translate(var(--uc-container-position-x), var(--uc-container-position-y));
 
   /* Shape */
   border-bottom: 2px solid var(--identity-icon-color);
-  width: calc(100% - 30px);
+  width: calc(100% - (var(--tab-inline-padding) + var(--tab-inner-inline-margin)) * 2);
   opacity: 0.75;
 }
 .tabbrowser-tab[visuallyselected] .tab-content::before {
@@ -51,7 +52,7 @@
     width: 25%;
   }
   .tabbrowser-tab[visuallyselected]:not([pinned]) .tab-content::before {
-    width: calc(100% - 30px);
+    width: calc(100% - (var(--tab-inline-padding) + var(--tab-inner-inline-margin)) * 2);
   }
   #tabbrowser-tabs[closebuttons="activetab"] .tabbrowser-tab[visuallyselected]:not([pinned]) .tab-content::before {
     width: calc(100% - 33px);
@@ -67,12 +68,15 @@
 }
 
 /* Pinned Tab */
-.tabbrowser-tab[pinned] .tab-content::before {
+.tabbrowser-tab[pinned] .tab-content::before,
+#tabbrowser-tabs[orient="vertical"]:not([expanded]) .tab-content::before {
+  left: unset;
   transform: translateY(var(--uc-container-position-y));
-  width: 16px;
+  width: 16px !important;
 }
 @include Option("userChrome.tab.close_button_at_pinned") {
-  .tabbrowser-tab[pinned][visuallyselected]:not([busy]):hover .tab-content::before {
+  .tabbrowser-tab[pinned][visuallyselected]:not([busy]):hover .tab-content::before,
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tabbrowser-tab[visuallyselected]:not([busy]):hover .tab-content::before {
     opacity: 0;
   }
   // Don't hide at userChrome.tab.close_button_at_pinned.background
@@ -80,13 +84,17 @@
 
 @include NotOption("userChrome.tab.container.on_top") {
   .tabbrowser-tab:is([image], [pinned])[usercontextid] > .tab-stack > .tab-content[attention]:not([selected])::before,
-  .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected])::before {
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tabbrowser-tab[image][usercontextid] > .tab-stack > .tab-content[attention]:not([selected])::before,
+  .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected])::before,
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[titlechanged]:not([selected])::before {
     opacity: 0;
   }
 
   /* Pinned Tab - Titlechanged Indicator override */
   .tabbrowser-tab:is([image], [pinned])[usercontextid] > .tab-stack > .tab-content[attention]:not([selected]),
-  .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]) {
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tabbrowser-tab[image][usercontextid] > .tab-stack > .tab-content[attention]:not([selected]), 
+  .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]),
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tabbrowser-tab[usercontextid] > .tab-stack > .tab-content[titlechanged]:not([selected]) {
     /* Original: radial-gradient(circle, var(--attention-icon-color), var(--attention-icon-color) 2px, transparent 2px); */
     --dotted-identity-image: radial-gradient(
       circle,
@@ -99,7 +107,9 @@
   }
 
   .tabbrowser-tab:is([image], [pinned]) > .tab-stack > .tab-content[attention]:not([selected]),
-  .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]) {
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tabbrowser-tab[image] > .tab-stack > .tab-content[attention]:not([selected]), 
+  .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]),
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tabbrowser-tab > .tab-stack > .tab-content[titlechanged]:not([selected]) {
     /* Original: center bottom calc(6.5px + var(--tabs-navbar-shadow-size)); */
     background-position-y: top var(--uc-container-position-y) !important;
   }
@@ -108,26 +118,42 @@
   .tabbrowser-tab:is([image], [pinned])[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
     > .tab-stack
     > .tab-content[attention]:not([selected]),
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tabbrowser-tab[image][usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+    > .tab-stack
+    > .tab-content[attention]:not([selected]), 
   .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
     > .tab-stack
-    > .tab-content[pinned][titlechanged]:not([selected]) {
+    > .tab-content[pinned][titlechanged]:not([selected]),
+    #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+    > .tab-stack
+    > .tab-content[titlechanged]:not([selected]) {
     --uc-titlechanged-container-position-x: calc(32% - 1px), calc(50% - 1px), calc(70% - 1px);
   }
   :root[uidensity="compact"]
     .tabbrowser-tab:is([image], [pinned])[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
     > .tab-stack
     > .tab-content[attention]:not([selected]),
+  :root[uidensity="compact"]
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tabbrowser-tab[image][usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+    > .tab-stack
+    > .tab-content[attention]:not([selected]), 
   :root[uidensity="compact"]
     .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
     > .tab-stack
-    > .tab-content[pinned][titlechanged]:not([selected]) {
+    > .tab-content[pinned][titlechanged]:not([selected]),
+  :root[uidensity="compact"]
+    #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tabbrowser-tab[usercontextid]:is([soundplaying], [muted], [activemedia-blocked])
+    > .tab-stack
+    > .tab-content[titlechanged]:not([selected]) {
     --uc-titlechanged-container-position-x: calc(30% - 1px), calc(50% - 1px), calc(70% - 1px);
   }
 }
 
 @include Option("userChrome.tab.container.on_top") {
   .tabbrowser-tab:is([image], [pinned]) > .tab-stack > .tab-content[attention]:not([selected]),
-  .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]) {
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tabbrowser-tab[image] > .tab-stack > .tab-content[attention]:not([selected]),
+  .tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected]),
+  #tabbrowser-tabs[orient="vertical"]:not([expanded]) .tabbrowser-tab > .tab-stack > .tab-content[titlechanged]:not([selected]) {
     /* Original: center bottom calc(6.5px + var(--tabs-navbar-shadow-size)); */
     background-position-y: top var(--uc-container-position-y-bottom) !important;
   }
diff --git a/src/tab/clipped_tab/_show_close_button_at_hover.scss b/src/tab/clipped_tab/_show_close_button_at_hover.scss
index 34bda20..a1a44f4 100644
--- a/src/tab/clipped_tab/_show_close_button_at_hover.scss
+++ b/src/tab/clipped_tab/_show_close_button_at_hover.scss
@@ -79,3 +79,14 @@
   padding-inline-start: 3px !important; /* Original: 0px */
   width: 19px !important; /* Redefine from 19px !important, Original: 17px = (width - padding)  */
 }
+
+#tabbrowser-tabs[orient="vertical"]:not([expanded]) .tab-close-button {
+  padding: 2px !important;
+  width: 16px !important;
+  height: 16px !important;
+  background-image: linear-gradient(var(--close-button-extra-background)), linear-gradient(var(--tab-selected-bgcolor, var(--toolbar-bgcolor))), linear-gradient(var(--toolbox-bgcolor)) !important;
+
+  &:-moz-window-inactive {
+    background-image: linear-gradient(var(--close-button-extra-background)), linear-gradient(var(--tab-selected-bgcolor, var(--toolbar-bgcolor))), linear-gradient(var(--toolbox-bgcolor-inactive)) !important;
+  }
+}
\ No newline at end of file
diff --git a/src/tab/selected_tab/_bottom_rounded_corner.scss b/src/tab/selected_tab/_bottom_rounded_corner.scss
index 533f73a..de1333f 100644
--- a/src/tab/selected_tab/_bottom_rounded_corner.scss
+++ b/src/tab/selected_tab/_bottom_rounded_corner.scss
@@ -94,8 +94,7 @@
     }
   }
 
-  &::is([lwtheme-mozlightdark], [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"])#{$lwtheme}
-    #TabsToolbar[brighttext] #tabbrowser-tabs:not([noshadowfortests]) .tabbrowser-tab[visuallyselected] .tab-background {
+  &#{$builtInDarkStyle} #TabsToolbar[brighttext] #tabbrowser-tabs:not([noshadowfortests]) .tabbrowser-tab[visuallyselected] .tab-background {
       &::before,
       &::after {
         /* As Selected Tab - Box Shadow */
diff --git a/src/tab/selected_tab/_box_shadow.scss b/src/tab/selected_tab/_box_shadow.scss
index 86a07ed..fb9b3b0 100644
--- a/src/tab/selected_tab/_box_shadow.scss
+++ b/src/tab/selected_tab/_box_shadow.scss
@@ -12,12 +12,30 @@ $ucTabBackgroundShadowHard: drop-shadow(-1px 0px 0px var(--uc-tab-shadow-color,
   --uc-tab-shadow-color-bundle: var(--tab-line-color, var(--lwt-tab-line-color, rgba(128, 128, 142, 0.9)));
 }
 
+#tabbrowser-tabs:not([noshadowfortests]) {
+  .tab-background:is([selected], [multiselected]) {
+    box-shadow: unset !important;
+    filter: $ucTabBasicShadow;
+  }
+
+  /* filter create new stacking context */
+  &[orient="vertical"] .tab-background:is([selected], [multiselected]) .tab-group-line {
+    height: calc(100% + 6px + var(--tab-block-margin)); // 6px: .tab-group-line's inset-block size
+    transform: translateY(-2px); // .tab-group-line 's inset-inline-start size
+  }
+  &[expanded][orient="vertical"] .tab-background:is([selected], [multiselected]) .tab-group-line {
+    inset-inline-start: calc(-1 * var(--tab-inner-inline-margin)) !important;
+  }
+  &:not([expanded])[orient="vertical"] .tab-background:is([selected], [multiselected]) .tab-group-line {
+    inset-inline-start: calc(-1 * var(--tab-inner-inline-margin) + 2px) !important;
+  }
+}
 #tabbrowser-tabs:not([noshadowfortests]) .tab-background:is([selected], [multiselected]) {
   box-shadow: unset !important;
   filter: $ucTabBasicShadow;
 }
 
-:root:is([lwtheme-mozlightdark], [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"])#{$lwtheme}
+:root#{$builtInDarkStyle}
   #TabsToolbar[brighttext] #tabbrowser-tabs:not([noshadowfortests]) .tabbrowser-tab {
   &:is([selected], [multiselected]) {
     > .tab-stack
@@ -37,7 +55,7 @@ $ucTabBackgroundShadowHard: drop-shadow(-1px 0px 0px var(--uc-tab-shadow-color,
 
 /* For themes outside of Light and Dark (which are curated by Mozilla), show a thicker border
    around the tab to help themes that are dependent on tab_line to show the selected tab. */
-:root:not([lwtheme-mozlightdark], [style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"])#{$lwtheme}
+:root:not(#{$builtInLightStyle})
   #TabsToolbar:not([brighttext])
   #tabbrowser-tabs:not([noshadowfortests])
   .tabbrowser-tab:is([visuallyselected], [multiselected])
@@ -48,7 +66,7 @@ $ucTabBackgroundShadowHard: drop-shadow(-1px 0px 0px var(--uc-tab-shadow-color,
           $ucTabAdditionalShadow;
 }
 
-:root:not([lwtheme-mozlightdark], [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"])#{$lwtheme}
+:root:not(#{$builtInDarkStyle})
   #TabsToolbar[brighttext]
   #tabbrowser-tabs:not([noshadowfortests])
   .tabbrowser-tab:is([visuallyselected], [multiselected])
diff --git a/src/theme/_fully_color.scss b/src/theme/_fully_color.scss
index 2808b0a..03ee6a1 100644
--- a/src/theme/_fully_color.scss
+++ b/src/theme/_fully_color.scss
@@ -100,10 +100,8 @@ html#main-window menupopup:not(.in-menulist) {
 }
 
 /* Default theme color preservation */
-:root[lwtheme-mozlightdark] menupopup:not(#BMB_bookmarksPopup, [placespopup="true"]), /* Legacy */
-:root[lwtheme-mozlightdark] menupopup:is(#goPopup, #historyMenuPopup, #bookmarksMenuPopup), /* Legacy */
-:root:is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]) menupopup:not(#BMB_bookmarksPopup, [placespopup="true"]),
-:root:is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]) menupopup:is(#goPopup, #historyMenuPopup, #bookmarksMenuPopup) {
+#{built-in-default-theme()} menupopup:not(#BMB_bookmarksPopup, [placespopup="true"]),
+#{built-in-default-theme()} menupopup:is(#goPopup, #historyMenuPopup, #bookmarksMenuPopup) {
   --menu-color: var(--toolbar-color, var(--in-content-page-color)) !important;
   --arrowpanel-background: var(
     --toolbar-bgcolor,
diff --git a/src/theme/system_default_theme/_mac.scss b/src/theme/system_default_theme/_mac.scss
index 8f34b91..b32aa10 100644
--- a/src/theme/system_default_theme/_mac.scss
+++ b/src/theme/system_default_theme/_mac.scss
@@ -247,7 +247,7 @@
       > .tabbrowser-tab
       > .tab-stack
       > .tab-background[selected],
-    :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][lwt-default-theme-in-dark-mode]
+    :root#{$builtInDarkStyle}
       #tabbrowser-tabs:not([movingtab])
       > #pinned-tabs-container
       > .tabbrowser-tab
@@ -259,7 +259,7 @@
       > .tabbrowser-tab
       > .tab-stack
       > .tab-background[selected],
-    :root[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"][lwt-default-theme-in-dark-mode]
+    :root#{$builtInDarkStyle}
       #tabbrowser-tabs:not([movingtab])
       > #tabbrowser-arrowscrollbox
       > .tabbrowser-tab
diff --git a/src/theme/system_default_theme/_win10.scss b/src/theme/system_default_theme/_win10.scss
index 0b5f1b4..42167db 100644
--- a/src/theme/system_default_theme/_win10.scss
+++ b/src/theme/system_default_theme/_win10.scss
@@ -354,7 +354,7 @@
     > .tabbrowser-tab
     > .tab-stack
     > .tab-background[multiselected]:not([selected]),
-  :root:is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"])
+  #{built-in-default-theme()}
      #tabbrowser-tabs:not([movingtab])
        > #pinned-tabs-container
        > .tabbrowser-tab
@@ -372,7 +372,7 @@
     > .tabbrowser-tab
     > .tab-stack
     > .tab-background[multiselected]:not([selected]),
-  :root:is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"])
+  #{built-in-default-theme()}
      #tabbrowser-tabs:not([movingtab])
        > #tabbrowser-arrowscrollbox
        > .tabbrowser-tab
diff --git a/src/utils/_theme.scss b/src/utils/_theme.scss
index 509baf9..2df04b2 100644
--- a/src/utils/_theme.scss
+++ b/src/utils/_theme.scss
@@ -9,13 +9,13 @@ $_lightText: '[lwthemetextcolor="bright"]';
 $_darkText:  ":not(#{$_lightText})";
 
 $_sysDark: "[lwt-default-theme-in-dark-mode]";
-$_lightStyle: '[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"]';
-$_darkStyle: '[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"]';
+$builtInLightStyle: ':is([style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"], [builtintheme][devtoolstheme="light"])';
+$builtInDarkStyle: ':is([style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rgba(251, 251, 254);"], [builtintheme][devtoolstheme="dark"])';
 
 //== Mixin =====================================================================
 @function built-in-default-theme() {
   $oldDefault: selector.append(":root", $_lightdark);
-  $newDefault: selector.append(":root", ":is(#{$_lightStyle}, #{$_darkStyle})");
+  $newDefault: selector.append(":root", ":is(#{$builtInLightStyle}, #{$builtInDarkStyle})");
 
   @return "#{$oldDefault}, #{$newDefault}";
 }
@@ -29,14 +29,14 @@ $_darkStyle: '[style*="--lwt-accent-color: rgb(28, 27, 34); --lwt-text-color: rg
 
 @function built-in-light-theme() {
   $oldLight: selector.append(":root", $_lightdark, $_darkText);
-  $newLight: selector.append(":root", $_lightStyle);
+  $newLight: selector.append(":root", $builtInLightStyle);
 
   @return "#{$oldLight}, #{$newLight}";
 }
 
 @function built-in-dark-theme() {
   $oldDark: selector.append(":root", $_lightdark, $_lightText);
-  $newDark: selector.append(":root", $_darkStyle);
+  $newDark: selector.append(":root", $builtInDarkStyle);
 
   @return "#{$oldDark}, #{$newDark}";
 }